Methods for treating chronic or unresolvable pain and/or increasing the pain threshold in a subject and pharmaceutical compositions for use therein

ABSTRACT

Methods are provided for reducing chronic inflammatory pain, increasing the levels of endogenous opioid peptides, as well as increasing the pain threshold of a subject having symptoms of androgen deficiency, comprising transdermally administering a composition comprising a bioactive androgen on a daily basis. In addition, the invention also relates to increasing the levels of endogenous opioid peptides in a human subject by administering an androgen composition to the subject. The invention also encompasses administration of a composition consisting essentially of an androgen for the treatment of chronic inflammatory pain, and for increasing the pain-threshold in a subject.

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/415,258, filed Nov. 18, 2010 and U.S. Provisional PatentApplication No. 61/534,174, filed Sep. 13, 2011, which applications areeach incorporated by reference herein in their entirety.

INTRODUCTION

The invention relates to the administration of a pain-reducing androgento a human subject in a safe and effective way. The invention relates toa method of reducing unresolvable chronic or acute pain (hereaftercalled either chronic pain or pain) in a human subject with androgendeficiency symptoms (as defined elsewhere herein) comprisingadministering a composition comprising a pain-reducing amount of anandrogen to a human subject, wherein the subject's androgen serum levelsare restored to safe levels within the reference range, such that painis reduced safely and effectively, as discussed in paragraphs[0018]-[0019]. This inflammatory or chronic pain described in theinstant invention is distinct and separate from fibromyalgia, asdescribed below in paragraphs [0023]-[0027].

The invention also relates to the administration of apain-threshold-increasing androgen to a human subject in a safe andeffective way in patients both with and without unresolved pain. Theinvention further relates to a method of increasing the pain thresholdof an human subject with androgen deficiency symptoms, as definedparagraphs [0008], [0029]-[0033], and [0041], comprising administering acomposition comprising a pain threshold-increasing amount of an androgento a human subject, wherein the subject's androgen serum levels arerestored to safe levels within the appropriate reference range so thatthe subject's pain threshold is increased safely and effectively.

The usage of androgens to treat unresolvable pain, or low thresholdpain, is unique. The present invention relates to pain due to chronicinflammatory pain states, and to the formulation of treatment strategiesthereof. Such chronic pain states have been seen as the focus fordeveloping the many different treatments for chronic pain. Therefore,conceptualization of most all treatment strategies has revolved aroundunderstanding the causes of pain for each of these pain states, eachbeing instructive as an example for the best approaches to therapy.Simply put, treatments had to be developed for each different type ofchronic pain. The present invention focuses on a different approach tothis population by seeing their pain as caused by a variety of biologicstressors, derived from either the environment and/or geneticpredisposition, that deplete androgen levels and induce androgendeficient states. Current standard practice pain therapies for treatingunresolvable pain do not include the androgen sex steroid hormone classof drugs. The same approach applies to treatment of patients with a lowthreshold of pain.

The androgen, as described for all embodiments of the invention, is anandrogen with biologic activity, also called “bioactive androgen” or“androgen.” It can be administered by a variety of means, including, butnot limited to, transdermal or transmucosal administration, oraladministration, time release capsule, by injection, and by suppository.The androgen can be administered on a daily basis. Alternatively, theandrogen can be administered to the subject over any period of timewherein the subject's pain is alleviated and/or the subject's painthreshold increased in a safe and efficacious manner. Also the androgencan be administered over any period of time to a subject without pain,wherein the subject's pain threshold is increased in a safe andefficacious manner. Further, the androgen can be administered toincrease the levels of endogenous opioid peptides in a subject.

BACKGROUND OF THE INVENTION

Current therapies for chronic or acute pain are often either ineffectiveand/or have substantive risks relative to the benefits. To date, it isdifficult to find reliable and satisfactory methods for addressingeither chronic or acute pain in patients that fail to resolve that painin such a way that they heal and achieve a feeling of well-being. Someof the more well-known therapeutics for pain involve the usage of: 1)the non-steroidal anti-inflammatory drugs or NSAID analgesics; 2) themorphine-related opioid analgesic class of drugs, such as oxycodone andhydromorphone; and 3) the usage of anti-depressants, for example theSerotonin-Norepinephrine Reuptake Inhibitor (SNRI) and SelectiveSerotonin Reuptake Inhibitor (SSRI) classes of drugs includingduloxetine, sertraline, venlafaxine, and fluoxetine, the tricyclic classof antidepressants; and cognitive behavioral therapy. However, all ofthese approaches suffer from either a lack of efficacy and/or unintendedside effects that are frequently worse than the benefits. For example,the NSAID class of analgesics, when used for chronic pain over a periodof time, can cause significant GI tract irritation. With respect to theopioid or morphine related class of drugs, recent data indicate thatchronic usage can even be responsible for and induce pain by itself(Mao, J., “Opioid-induced Abnormal Pain Sensitivity,” Current Pain andHeadache Reports, 2006, 10:67-70). In addition, side effects for opiatesinclude nausea and vomiting, confusion, compromised immune function,subnormal testosterone levels in males leading to osteoporosis,addiction, lack of efficacy over time (tolerance), and constipation. Theanti-depressants are well known in the clinical realm as having sexualdysfunction side effects, including arousal disorder, ejaculationfailure and difficulty achieving orgasm, as well as an FDA mandatedblack box warning for increased risk of suicidality. Other common sideeffects for anti-depressants include nausea, insomnia, dizziness,tremor, and decreased libido.

The sex steroid hormones are normally considered to be important in theclinic for sexual health, but have never been used in routine practiceor as standard therapy in the clinic to reduce chronic pain. Androgens,estrogens and progestins, or their agonists and antagonists, are used byreproductive endocrinologists within the clinic to treat sexualdisorders. The use of these hormones are not normally thought of outsidethe context of sexual function such as reproduction and secondary sextraits. However, more recently, it has been recognized that estrogens,for example, are important in the health of men for bone plate formation(Smith et al., The New England Journal of Medicine, 1994, 331:1056-1061;Ohlsson and Vandenput, European J. of Endocrinology, 2009, 160:883-889).Likewise, it is plausible that androgens are important for overallhealth beyond their role in reproduction. The instant invention relatesto the importance of healthy serum levels of testosterone fornon-reproductive neuroendocrine health for reducing pain and/orincreasing pain threshold, and to foster feelings of well-being. Thereis also accumulating evidence that the sex hormones, in particularestrogens, progestins, and now testosterone, can be correlated tosubjective feelings of well-being and quality of life. In fact, eithertoo high or too low levels of the sex steroid hormones, includingtestosterone, result in a loss of feeling of well-being. Specifically,testosterone can have an effect on dopamine, serotonin,N-methyl-D-aspartic acid (NMDA), and enkephalinergics, all of whichcontribute to feelings of well-being and modulation of mood. The bestway to evaluate testosterone deficiency in the clinic is to look forclinical symptoms of too-low androgen levels in a human subject whoseblood serum levels are in the lower half of the reference range.

Clinical symptoms of androgen insufficiency may include, but are notlimited to, loss of libido, bouts of impotence, chronic fatigue,insomnia, hot flushes, sweating, alopecia or hair loss, mood change,mood swings, nervousness, loss of feelings of well-being, anemia such asthat caused by insufficient erythropoietin production, impaired memory,inability to concentrate, Alzheimer's Disease (patients with androgeninsufficiency have a higher risk), andropause (low production ofandrogens), night sweats, anovulatory menstrual cycles, amenorrhea,menorrhagia, menometrorragia, metrorrhagia, oligomenorrhea,polymenorrhea, decrease in muscle mass, osteoporosis, compressionfractures, and obesity (unhealthy fat to muscle ratios) (see paragraph[0041]). In addition, disorders such as diabetes, hypertension,Klinefelter's, Wilson-Turner and Androgen insensitivity syndromes canproduce hypogonadism.

Acute vs. chronic pain. Acute pain is a sensation that is normallytriggered in the nervous system to alert an individual about possibleinjury and the need to respond to the situation. Chronic pain isdifferent. Chronic pain, usually inflammatory in nature, has beendefined by the National Institute for Neurological Disorders and Strokeas persistent pain, which can last as long as six months or more. Here,pain signals keep firing in the nervous system for weeks, months, evenyears. There may have been an initial mishap, such as a sprained back,or serious infection, or there may be an ongoing cause of pain, such asarthritis, cancer, or an ear infection, but the nervous systeminappropriately fails to dampen and thereby resolve the painful insult.Some people suffer chronic pain in the absence of any past injury orevidence of body damage. Temporal summation of pain and “wind-up”phenomena, whereby pain is amplified in intensity over time and thepainful area increases in size, are thought to be involved, although thebiologic mechanisms for controlling pain remain poorly defined.Furthermore, the reasons why some people are more susceptible to painthan others has not been well understood. Many chronic pain conditionsaffect older adults, but they are not limited to older adults. Commonchronic pain complaints include headache, low back pain, cancer pain,arthritis pain, neurogenic pain (pain resulting from damage to theperipheral nerves or to the central nervous system itself), andso-called “psychogenic” pain (pain not due to past disease or injury orany visible sign of damage inside or outside the nervous system, but topsychological trauma, for example). Here we define pain as unresolvablechronic or acute inflammatory pain, or an abnormally low pain thresholddue to stress/distress on/within the individual that is unresolvable.

There are numerous conditions that are accompanied with, or caused bypain, some of which involve chronic pain. There are also numeroustheories relating to the treatment of chronic pain. Presently, there isextensive ongoing research relating to pain, how pain is transmittedthrough and perceived by the body, and treatments to overcome, or atleast alleviate pain. The importance of receptors in the body and howsome neurotransmitters function is being studied (See, e.g., Millan,2000, Prog. Neurobiol. 66:255-474), although effective treatment of painin the clinic remains problematic.

Stress on an individual can be resolved (“eustress”), but when stress isunresolvable by the individual (“distress”), it can be the basis ofunresolvable pain. It is known that chronic pain can be the result of awide variety of stressor conditions and stressor states, includingdisease, surgery, various types of trauma and/or physical distress.Emotional distress such as grief, and pathologic states within theimmune system, nervous system, endocrine system, and other biologicsystems can also act as stressor states that contribute to pain. Suchstress can lead to unresolvable pain in both females and males. Selyedefines stress as a “non-specific response of the body to any demand. Astressor is an agent that produces stress at any time.” (Selye, CMAJournal, 1976, 115:53-56 at 53). Selye's “general adaptation syndrome”recognizes three phases in an individual's resistance to stress: theinitial alarm, resistance to that alarm, and if not resolved,exhaustion. Further, Selye coined the term “eustress” in which theindividual responds to a stressor such that adaptation and copingresponses resolve the stress, as opposed to “distress” in which theindividual's stress response fails to be resolved. However, it is notwell understood why, despite cognitive behavior modification training,for example, some individuals are able to adapt so much better thanothers, or why an individual who has previously been able to adapt canno longer do so. In other words, sometimes the individual can adapt tothe stress such that the stress is resolved, while in other situationsthe individual cannot adapt, and the stress on the individual remainsunresolved. When the stress is resolved, the result is a state ofeustress. When the stress is unresolvable, the result is a state ofdistress and a lack of feeling of well-being, resulting in pain and/orillness. Part of the problem is our poor understanding of how thevarious neuroendocrine and immunologic pathways modulate our responsesto stress, and promote or fail to promote eustress and feelings ofwell-being in an individual. It is not widely appreciated that stress,by itself, can catabolize and exhaust the body's supply of androgens, asexemplified by individuals studied during combat training (Opstad, P.K., et al., J. Clinical Endocrinology & Metabolism, 1992, 74:1176-83).The instant invention here is that androgen therapy can restore healthyserum levels of androgen and thereby ameliorate distress, can partiallyor completely resolve that stress, and can reestablish a state ofeustress along with feelings of well-being. Further, androgen therapythat restores stress-depleted androgen levels to effective and safelevels, while providing significant clinical responses without clinicalevidence of androgen excess, is driven largely by effective processingand dampening of pain, the mechanism for which is clearly laid outherein. Finally, in one embodiment, the instant invention encompassesthe use of androgen therapy to enable stress to be processed and pain tobe decreased.

Current treatment of unresolvable inflammatory pain. Treatment forchronic inflammatory pain includes some of the same treatments for acutepain, including opioids, non-opioid analgesics, and anti-inflammatorydrugs. Treatment of chronic pain can also include additional approaches,such as, antidepressants, acupuncture, local electrical stimulation, andbrain stimulation, as well as surgery. Some physicians use placebos,which in some cases has resulted in a lessening or elimination of pain.Psychotherapy, relaxation, and medication therapies, biofeedback, andbehavior modification may also be employed to treat chronic pain.

Sex steroid hormones, notably androgens, can be important for painprocessing. There is some evidence that both androgens and estrogensplay a role in pain sensation in animal models, although this has notbeen adequately studied or approved in humans for chronic pain. Further,it appears that gender can have an impact on the sensation of pain. Itis well known, for example, that testosterone decreases the productionof sex hormone binding globulin (SHBG), while estradiol increases SHBGproduction. SHBG acts to sequester sex steroid hormones away from thebioavailable pool, preventing entry of sex steroid hormones across theblood-brain barrier (BBB) into the central nervous system. There isevidence that the blood-brain barrier is more permeable to testosteronethan estradiol; in rodents, the fetus has a SHBG-like protein,fetoneonatal estrogen binding protein (alpha-fetoprotein) that isthought to act to sequester peripheral estrogen, but not testosterone,away from the central nervous system (MacLusky et al., Science, 1981,211:1294). In addition, the concept that SHBG can prevent entry of sexhormones through the blood-brain barrier to the central nervous systemhas been shown in a human-into-rodent model (Pardridge W. M. et al. TheAmerican Journal of Physiology, 1980, 239:1 E103-E108). These findingsare consistent with the theory that it is testosterone rather than17-beta estradiol that most effectively transits from serum through theblood-brain barrier and into the central nervous system to mediateanti-nociception. It is the nociceptive relay neurons in the spinal cordthat are well known to be important for transmitting pain signals, andconversely they can also be involved in dampening pain.

Gonadal or sex steroid hormones down-regulate inflammatory cellresponses. It is well known that there is an inverse correlation betweengonadal steroid hormones (estrogens, progestins and androgens) andinflammation. First, at puberty gonadal steroid hormone serum levelssurge when the thymus correspondingly undergoes “involution,” in whichthere is decreased thymic cellularity, decreased thymic celldevelopment, and decreased thymic cell output to the periphery asmeasured by recent thymic emigrants (RTE) (a good measure of peripheralthymic cells, also known as T cells or T lymphocytes, which are criticalfor inflammation). Second, during pregnancy, the acute surge in gonadalsteroid hormone serum levels that occurs results in further thymicinvolution, and consequently greatly decreased numbers of peripheralthymocytes which would otherwise recognize the embryo as foreign andreject it. Concomitant with the decreased thymic T cell output inpregnancy is a high susceptibility to infection, for example the highrisk of pregnant women to infection from rubella (measles), which can beabortogenic (which is in itself an inflammatory response that overcomesthe mother's immunologic tolerance of the fetus, thereby rejecting it asforeign) or result in severe harm to the fetus. In fact, researchers usethis increased susceptibility to infection in pregnancy to successfullyinfect animals with pathogens (pathogens which would otherwise beeliminated by the immune system) to create animal model systems forstudying those pathogens. Third, gonadectomy (e.g., ovariectomy ofanimals) results in a reversal of thymic involution, restoration ofthymic cellularity and thymic output, and an increased T cell repertoire(in both diversity and numbers) in the periphery (Perisic M. et al.,“Role of ovarian hormones in age-associated thymic involutionrevisited,” Immunobiology, 2010, 215(4):275-293). Fourth, rescue ofgonadectomy with exogenous hormone by injection of gonadal steroidhormones into animals decreases the numbers of thymocytes and T cells inthe periphery (Zoller A. L. et al., “Murine pregnancy leads to reducedproliferation of maternal thymocytes and decreased thymic emigration,”Immunology, 2007 121(2):207-215).

Hormone replacement therapy in women has focused on estrogens andprogestins, but not on androgens. The Women's Health Initiative (WHI)clinical trial, whose aim was to prospectively evaluate the risks andbenefits of orally administered combination hormone replacement therapyin healthy women using estrogens and medroxyprogesterone acetate, wasrelatively recently halted (Fletcher, S. W., et al., J. Amer. Med.Assoc., 2002, 288: 366-368). The increased risks in coronary heartdisease, breast cancer, stroke, and pulmonary embolism outweighed theincreased benefits in colorectal cancer, endometrial cancer, hipfractures and death due to other causes, resulting in a small butstatistically significant increased risk for the global index of hazardratios among women taking these hormones. The authors pointed out,however, that their study only evaluated healthy women, not those withsymptoms of hormone deficiency. This means that the treatments wouldhave raised the serum levels of hormones to a level exceeding the normallevels of hormones for women of the same age. Furthermore, thesetreatments were orally administered. Other routes of delivery, e.g.,transdermal systems, need to be studied, since it is possible thattransdermal delivery may increase benefits and/or decrease risks tothese patients. It was noted by the authors of the WHI study thathormone replacement therapy is still considered to be effective forrelieving peri-menopausal symptoms such as hot flashes. Since thecompletion of the WHI trial, it has also been found that hormonereplacement therapy has greater benefits and rare risks in women aged50-59, a younger age group relative to the WHI trial (van de Weijer etal., Maturitas, 2008, 60:59). On Mar. 31, 2009, methyltestosteronecombined with estrogens (Solvay's ESTRATEST®), prescribed to women forhot flashes when they failed to get relief from estrogen replacementtherapy, was taken off the market because Solvay never demonstratedefficacy to the FDA. The FDA's new regulation system (Drug EfficacyStudy and Implementation, DESI) required additional studies onESTRATEST® to prove drug efficacy, which forced ESTRATEST® to fall underthe unapproved drugs category on the FDA's DESI list.

Androgen therapy is effective against muscle wasting, for example inAIDS, but has not been approved to treat chronic inflammatory painstates. Most clinical trials evaluating sex hormone replacement therapyhave focused on estrogens and progestins in women. Testosteronereplacement therapy in individuals who may be testosterone deficient isnow beginning to be addressed using transdermal delivery systems. Forexample, disease states in which there is loss of muscle mass may betreated with transdermal testosterone administration. This includeswasting syndrome in women with AIDS (Miller, K., et al., J. Clin.Endocrinol. Metab., 1998, 83:2717-2725; Javanbakht, M. et al., J. ofClinical Endocrinology & Metabolism, 2000, 85:2395-2401).

However, there is still an unmet need to develop therapeutic agents forpain that are both safe and effective, and with minimal adverse sideeffects, for chronic pain. In addition, there is a need to providetreatment for unresolvable chronic and acute pain that is oftenexperienced by both females and males who are deficient in androgens,such as testosterone.

SUMMARY OF THE INVENTION

Androgens can be useful for modulating the sensation of pain anddistress; thus, androgen therapy can be used to treat unresolvablechronic inflammatory pain states or their associated states of distress.The present invention relates to chronic pain states, and to theformulation of treatment strategies thereof. The basis of the inventionresides in the treatment with testosterone of chronic pain due tostressor states that affect males and females, said stressor stateshaving a significant impact on pain sensation in such patients becauseof causing an androgen deficient state or symptoms of androgendeficiency (“distress”). Thus, there is a need to provide treatment forchronic pain experienced by both females and males who are deficient inandrogens, including testosterone, such that chronic pain or a stressorstate is alleviated.

The fundamental basis or foundation of the invention here (to treatchronic inflammatory pain with androgen therapy) is the combination ofthese disparate observations in animals into a unifying pathway (the“Circle Hypothesis”) that provides a mechanistic basis by whichandrogens dampen or down-modulate chronic pain in humans. FIGS. 3A-3B,described more fully below in paragraphs [0042]-[0046], show thehypothesized metabolic pathway for testosterone in relation tonociception in the central nervous system. Normally, a painful stimulusor state of stress upregulates Substance P, which is, in effect, asignal for pain or stress in the CNS. Pain or stress also causesserotonin levels to drop, thus reducing feelings of well-being.Substance P, in turn, stimulates aromatase within the spinal cordnociceptive relay neurons. This Substance P regulation of aromatase ismediated by protein kinases and phosphoprotein phosphatases which canact quickly and in a complex way to allow the body to respondappropriately to pain and stress. Testosterone, as the substrate foraromatase, can cross the blood-brain barrier much more readily thanestrogens (the transit of sex steroid hormones across the blood-brainbarrier (BBB) is highly regulated by sex hormone binding globulin aswell as aromatase enzymology), thus allowing aromatase in the spinalcord nociceptive relay neuron to convert testosterone to 17-betaestradiol within the central nervous system. Enkephalins (opioidpeptides) are expressed within the spinal cord nociceptive relay neuronsin response to 17-beta estradiol, resulting in the dampening of pain andthe negative feed-back down-regulation of Substance P, and therebybringing the pathway full circle back to a resting state. In patientshaving unresolved chronic inflammatory pain or other stressors ortrauma, however, this cycle is “frustrated,” and cannot progress:testosterone is exhausted and depleted in response to the unresolvedchronic inflammatory pain or stressor state, resulting in a depletion of17-beta estradiol in the spinal cord, a failure to produce opioidpeptides, such as enkaphalins, and a failure to alleviate thepain/stress state. Thus, insufficient testosterone levels not only failto allow for recovery from the initial painful stimulus or stressor, butthey can also contribute to the chronic pain state and help establish astate of distress (defined elsewhere). In addition to the spinal cord,aromatase is also found in the brain and the periphery, allowing forthese mechanisms to take place in both the CNS and the periphery inresponse to pain or stress. This Circle Hypothesis is discussed ingreater detail below in paragraphs [0042]-[0046].

Background on Androgens. Generally, the androgen used in the inventionis a biologically active androgen. Biologically active androgens may beactive in their native state, may be a precursor or pro-drug that ismetabolized to a biologically active state upon ingestion by thesubject. The biologically active androgen may be, but is not limited to,testosterone, androstenedione, androstendiol, dehydroepiandrosterone,danazol, fluoxymesterone, oxandrolone, nandrolone decanoate, nandrolonephenpropionate, oxymethalone, stanozolol, methandrostenolone,testolactone, pregnenolone, dihydrotestosterone, methyltestosterone,bioactive androgen precursors, or testosterone esters. Although theinvention may incorporate use of any of the above (or other) androgens,testosterone is frequently discussed as an exemplary androgen compound.

Androgens bind not only to androgen receptors, but they also are able toact within cells via androgen receptor (AR) independent pathways toameliorate and reverse the physiological consequences of lowtestosterone and resultant loss of feelings of well-being. The instantinvention can act both at the AR level and the AR-independent level toreduce androgen deficiency symptoms. The treatments of the invention, asprimary therapies, can either replace or be used in combination withother pharmacological agents. One of ordinary skill in the art, based onthese teachings, would be able to discern the patients who might benefitfrom such a treatment and determine the effective and safe dosage foruse in patients.

Androgens can modulate pain. In animal models, pain appears to bereduced during pregnancy via opiate production, when testosteroneconcentrations are elevated. Anecdotal evidence suggests that there is ahigh risk of pain symptoms in women who have undergone bilateraloophorectomy (testosterone is produced in the ovaries and adrenalglands), and conversely, symptoms appear to temporarily abate forpatients during pregnancy. It is known that during pregnancy, migraineheadache frequency declines and temporomandibular disorder (TMD) pain isreduced, and after pregnancy, when the sex steroid hormone levels candrop more severely than usual, feelings of well-being can be lost(Sances G. et al., Cephalagia, 2003, 23:197-205).

Androgens can improve clinical symptoms of non-inflammatory fibromyalgiapatients (a counter-intuitive concept since androgens have historicallybeen considered reproductive hormones rather than hormones that impactpain responses). The vast scientific literature on androgens and the sexsteroid hormones in general relates to their ability to promotereproduction. And androgens in particular are notable for their role andabuse potential in promoting muscle strength.

White et al. (U.S. Pat. No. 5,935,949 and U.S. Pat. No. 7,799,769)previously conducted studies that provide initial proof of concept thattestosterone given transdermally to female fibromyalgia patients couldboth significantly and safely raise serum hormone concentrations frombaseline levels to levels that approximate those normally found inpremenopausal women, as well as significantly improve the symptoms ofnon-inflammatory fibromyalgia tender point pain along with otherfibromyalgia symptoms that, taken together, uniquely define thissyndrome, all without inducing any of an extensive list of symptoms ofandrogen excess.

Neither U.S. Pat. No. 7,799,769 nor U.S. Pat. No. 5,935,949 relate to orcover the non-fibromyalgia chronic inflammatory pain states of theinstant invention, as described in paragraphs [0025]-[0029]. It is clearthat fibromyalgia muscle tender point pain, as discussed above in theafore-mentioned patents, is distinct from most other types of pain, andthat androgen hormone therapy has not been considered for reducingnon-fibromyalgia, chronic inflammatory pain in the clinic or unresolvedstress conditions with low pain thresholds.

Chronic inflammatory pain is clinically distinct from fibromyalgiamuscle tender point pain. It is clear that chronic inflammatory pain isa distinct clinical entity from fibromyalgia-related tender pointnon-inflammatory pain. This conclusion is based on: 1) Diagnostic andStatistical Manual of Mental Disorders (DSM) criteria for medicaldiagnosis are distinctly different; 2) fibromyalgia is a diffuse illnessof unknown mechanism and defined by distinctly widespread and painfultender points above and below the waist and on the right and left sides;the cause of chronic inflammatory pain is generally known and can relateto pathology of bones, nerves, and connective tissue as found, forexample, in autoimmunity, cancer, infectious diseases and injury(although other stressors can induce chronic inflammatory pain); 3)erythrocyte sedimentation rate is not changed for fibromyalgia patients,but is elevated for chronic inflammatory pain states; 4) most patientswith chronic inflammatory pain see a neurologist or anesthesiologist fortreatment, while fibromyalgia patients generally see a rheumatologist;5) the treatments and analgesics used for each group are generallydifferent (chronic inflammatory pain patients are prescribed medicationssuch as analgesics, opioids, muscle relaxants—as for lower back pain;fibromyalgia patients receive antidepressants and/or sedative for sleep,along with analgesics); 6) immobilization is often required forneurologic inflammatory pain due to injury or accident, butimmobilization is discouraged for fibromyalgia patients; 7) fibromyalgiapain occurs mostly in women whereas males and females are equally atrisk for chronic inflammatory pain.

Clinical testing for chronic inflammatory pain patients is distinct fromthat for fibromyalgia patients. Further, there are different tests thatcan be performed by physicians, which can also give an indicationregarding the etiology of certain conditions and a way of classifyingthe patient's condition. For example, a laboratory test known as theerythrocyte sedimentary rate, or “sed rate,” measures the rate at whicha patient's red blood cells settle to the bottom of a tube or assayvessel over a prescribed period of time. This is a non-specific testthat indicates the presence of an inflammatory process in a patient.Inflammatory responses are an indicator of immune system-derivedmediators from white blood cells that signal pain to the nervous system.And it is the neurologist who normally treats chronic inflammatory painstates. All chronic inflammatory pain states have positive, or elevated“sed rates,” confirming the inflammatory process. Fibromyalgia, on theother hand, is distinct from chronic inflammatory pain, in thatfibromyalgia is a rheumatologic illness, and such patients have “sedrates” that are unchanged from “normal” sed rates. This indicates thatfibromyalgia is caused by a very different process than what typifiesthe autoimmune or infectious disease states, for example, of chronicinflammatory pain. Further, for patients with chronic inflammatory pain,testosterone levels can be exhausted, and a low testosterone level canlead to a hyperinflammatory state, thus exacerbating the chronicinflammatory pain state. Patients exhibiting chronic inflammatory painare likely to visit a neurologist, whereas a fibromyalgia patient islikely to see a rheumatologist. Generally, these two distinct sets ofdoctors are uniquely versed in different treatments. For example, arheumatologist who sees a large number of fibromyalgia patients wouldnot look to the same treatments as a neurologist, the doctor mostchronic inflammatory patients would see. These are two different worldsof medicine and the neurologist pain doctor is unlikely to reviewfibromyalgia treatments for methods of treating chronic inflammatorypain. For example, the neurologist is likely to prescribe opioidanalgesics, which will have the unintended consequence of actuallylowering testosterone levels and exacerbating the pain.

The skilled practitioner in medical technology for the instant inventionwould not apply a testosterone gel therapeutic developed fornon-inflammatory fibromyalgia tender point chronic pain to patients withinflammatory chronic pain. A clinician who treats inflammatory chronicpain patients would, at this time, be constrained on several levels fromtreating their patients using a therapeutic developed for fibromyalgiapatients. First, prior to the instant invention, a mechanistic basis forthe efficacy of a testosterone therapeutic for chronic inflammatory painin humans had not been elucidated. Second, current paradigms of clinicalpractice, as well as reimbursement constraints, hold doctors to bestpractices that are limited to evidence-based mechanistic pathways thatunderlie pain. In fact, doctors are becoming ever more constrained touse evidence-based best-practice medicine. Thus, current medicalpractice, up to now, has failed to link concepts underlying reproductiveimmunology (White et al., “CD3+CD8+ CTL Activity Within the Human FemaleReproductive Tract,” J. Immunol., 1997, 158(6):3017-3027), ortherapeutics for fibromyalgia tender point pain (see U.S. Pat. Nos.5,935,949 and 7,799,769), with androgen therapeutics for chronicinflammatory pain as described herein. Specifically, the “circlehypothesis” described in paragraphs [0042]-[0046] has never beenadvanced prior to the instant invention. Third, off-label prescribing islimited by the FDA, which has stepped up its litigation against this,especially for therapeutics with abuse potential.

Identifying patients with chronic inflammatory pain states and clinicalsigns and symptoms of androgen deficiency. A) Reducing chronicinflammatory pain with androgen therapy. The instant invention relatesto a method of reducing chronic inflammatory pain or state of distressin a human subject comprising diagnosing a human subject to have 1) anyone of the following: a) elevated C-reactive protein, b) elevatederythrocyte sedimentation rate, c) any one of the following DSM-IVdefined Disorders: Pain Disorder Associated With Psychological Factors307.80, Pain Disorder Associated With Both Psychological Factors and aGeneral Medical Condition 307.89, Dementia including Alzheimer's Typeand Vascular Dementia 290, Alcohol-Related Disorders 291, DrugWithdrawal and Psychotic Disorders 292, Mood, Anxiety, and MentalDisorders 293, Dementia, Cognitive, and Amnestic Disorders includingHead Trauma 294, Mood Disorder 206.90; Anxiety Disorders 300, Male andFemale Sexual Disorders 302.70-302.74, 302.9; Alcohol and DrugDependence Disorders 303, Alcohol, Drug, and Nicotine Abuse 305; SleepDisorders 307.42; Acute Stress Disorder 308, Adjustment Disorders,including Post Traumatic Stress Disorder 309, Personality Disorders 310;Depressive Disorders 311; Sleep Disorders 327, Neuroleptic-InducedDisorders 332, 333; Male Sexual Disorders 607/608, Female SexualDisorders 625; Age-Related Cognitive Decline 780.93, d) clinicalsymptoms of androgen deficiency, as described in paragraphs [0008],[0029]-[0033], and [0041], or e) an unresolved state of distress asdescribed elsewhere herein, for example, in paragraph [0041]; and 2)determining if the subject has androgen levels in the lower half of theappropriate reference range. If the subject has at least one of theindications defined by (1) above, along with 2) androgen levels in thelower half of the appropriate reference range; a pain-reducing amount ofa composition comprising an androgen can be administered to a humansubject, wherein pain is reduced safely and effectively or the state ofdistress is ameliorated.

Identifying patients with chronic inflammatory pain states and clinicalsigns of androgen deficiency. B) Increasing a patient's pain thresholdwith androgen therapy. The instant invention also relates to a method ofincreasing the pain threshold of a human subject comprising diagnosing ahuman subject to have any one of the indications defined by (1) inparagraph [0029] above; determining if the subject has androgen levelsin the lower half of the appropriate reference range; and, if thesubject has at least one of the indications defined by (1) in paragraph[0029] above, along with androgen levels in the lower half of theappropriate reference range; administering a composition comprising apain threshold-increasing amount of an androgen to a human subject,wherein the subject's pain-threshold is increased safely andeffectively.

Testing and assessing patients for androgen therapy. The instantinvention further relates to a method for determining if a human subjectwould benefit from androgen administration comprising any combination ofthe following tests and evaluations, as needed: A) testing for any oneof the indications defined by (1) in paragraph [0029] above, B) testingthe subject's serum to determine if their androgen levels are in thelower half of the appropriate reference range; C) assessing the subjectfor clinical symptoms of androgen deficiency which may include, but isnot limited to, loss of libido, sexual dysfunction, chronic fatigue,anemia, low muscle:fat ratio, and alopecia, D) assessing levels of pain,E) assessing the subject's pain threshold, and/or F) testing usingmetrics that may include, but are not limited to, those for evaluatingpain, physical function, psychological function, global health andsleep. If the subject meets the criteria for androgen treatment, acomposition comprising an androgen can be administered to the subject,wherein the subject's androgen serum levels are restored to themiddle-upper range of an appropriate reference range.

The invention also relates to a kit for determining if a human subjectwould benefit from androgen administration comprising instructions fordiagnosing a subject as having an androgen-deficiency treatable byadministration of an androgen. The instructions can comprise instructinga health care provider how to test the subject's androgen serum levelsand how to determine if the subject meets any of the criteria inparagraph [0029]. The instructions can further comprise instructing thehealth care provider how to test the subject's pain threshold; andinstructing the health care provider to administer a compositioncomprising an androgen to the subject if the subject has androgen levelsin the lower half of the of the appropriate reference range, a lowthreshold of pain, and at least one of the indications in (1) inparagraph [0029] above; so that the subject's androgen serum levels arerestored to the middle-upper portion of an appropriate reference range,and clinical symptoms or the low pain threshold are improved safely andeffectively.

The invention also relates to a method of increasing endogenous opioidpeptide production in an androgen-deficient, endogenous opioidpeptide-deficient human subject. The method comprises diagnosing a humansubject to have at least one of a) elevated C-reactive protein, b)elevated erythrocyte sedimentation rate, c) DSM-IV disorder 307.80, d)DSM-IV disorder 307.89, or e) an unresolved stressor state; determiningif the subject has androgen levels in the lower half of the appropriatereference range; determining if the subject low endogenous opioidpeptide levels; and, if the subject has at least one of a) elevatedC-reactive protein, b) elevated erythrocyte sedimentation rate, c)DSM-IV disorder 307.80, d) DSM-IV disorder 307.89, or e) an unresolvedstressor state, along with androgen levels in the lower half of theappropriate reference range and low endogenous opioid peptide levels;administering a composition comprising an androgen to a human subjectwith androgen and opioid peptide deficiencies, wherein the subject'sproduction of endogenous opioid peptides is increased.

In accordance with the present invention, androgen therapy is theprimary therapy to be administered for all of the above embodiments ofthe invention. Further, in accordance with the invention, subjectsreceiving primary androgen therapy may also receive adjunctive opioidtherapy if they have exogenous opioid-induced hypogonadism or otherconditions that might require such adjunctive opioid therapy in additionto the primary androgen therapy. Further, while androgens remain theprimary therapy for the methods of the instant invention, othercompounds, such as, but not limited to, antidepressants may also beadministered as adjunctive therapies.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain aspects of the instant invention may be better understood byreferences to the detailed description when considered in connectionwith the accompanying Figures.

FIGS. 1A-1C show that the serum total testosterone concentrations in apopulation of female patients are increased in response to testosteronegel therapy.

FIGS. 2A-2C show that the free testosterone concentrations in apopulation of female patients are increased in response to testosteronegel therapy.

FIGS. 3A-3B depict the hypothesized metabolic pathway for testosteronein relation to nociception in the central nervous system in normal (A)and deficient (B) subjects.

DETAILED DESCRIPTION OF THE INVENTION

While the present disclosure may be embodied in many different forms,the drawings and discussions are presented with the understanding thatthe present disclosure is an exemplification of the principles of one ormore inventions and is not intended to limit any one of the inventionsto the embodiments illustrated.

Why androgen therapy is effective against unresolved pain, unresolvedstates of distress, or decreased tolerance to pain. The inventionrelates to how and why androgens are a critical part of painpathophysiology, such that when androgens are given therapeutically toindividuals with chronic inflammatory pain, the androgen treatmentshould significantly resolve that pain. By “androgen therapy” it ismeant to include administration of a single androgen or a combination ofandrogens. Administration of the androgen can be a single administrationor administration over a period of time. By “alleviate” it is meant tomake less hard to bear, reduce or decrease, or lighten or relievepatients of the symptoms of an illness or a condition. By“androgen-deficient” or “androgen deficiency” it is meant that 1) apatient's testosterone serum levels are in the lower half of thereference range, and concomitant with at least one of the following: 2a)the presence of chronic or acute unresolved inflammatory pain (painassessment as defined elsewhere herein) or state of distress or symptomof androgen deficiency, as described in paragraph [0028], 2b) the lackof a feeling of well-being combined with a low threshold of pain(threshold testing as defined elsewhere herein), or 2c) a failure toadapt to or resolve stress (stressors as defined elsewhere as amaladaptive and unresolved state of “distress”). By “primary therapy” itis meant to be the main or first-line therapy given to a subject for thetreatment of chronic inflammatory pain, for increasing thepain-threshold of a subject, or for increasing a subject's productionand/or levels of endogenous opioid peptides. By “adjunctive therapy” or“adjuvant therapy,” it is meant to be a secondary therapy, given to asubject to augment or complement the subject's primary therapy.

Pain and stressor states are related and defined. Further, the focus ofthe present invention is on pain associated with stressors of variouskinds, including, but not limited to: 1) PTSD, which includes combat orshell shock or Gulf War Syndrome, 2) accident, 3) trauma, 4) surgery, 5)autoimmune disease such as rheumatologic disorders, including arthritis,6) chronic unresolved or acute viral infection, 7) infectious disease,8) cancer, 9) chronic exhaustion or physical distress, 10) neuropathy,11) hyperalgesia, 12) allodynia, 13) grief, emotional distress, ordepression, 14) surgical or pharmacologic-induced gonadectomy, or 15)dysthymia. Also included are pain states with elevated levels of serumor cerebrospinal fluid Substance P, plus pain states with reduced levelsof serum or cerebrospinal fluid endorphins and/or serotonin, dopamine,NMDA or enkephalinergics, all of which can cause chronic pain in femalesand in males. DSM-IV disorder coding for these conditions include code307.80, “Pain Disorder Associated with Psychological Factors”(psychological factor plays a major role in pain); and code 307.89 “PainDisorder Associated with Both Psychological Factors and a GeneralMedical Condition” (psychological factors may or may not play a role inpain); including both acute and chronic pain; and including locationssuch as abdominal, back, bone, head or brain, legs, arms, internalorgans, skin, immune system, nervous system and chest. Additionaldisorders that can affect pain are listed in paragraph [0029] above.Stress, eustress and distress are defined above in paragraph [0011].Further, a subject may have a chronic medical state accompanied by anadditional stressor state, that causes or exacerbates chronic pain.

The fundamental basis or foundation of the instant invention (to treatchronic inflammatory pain with androgen therapy) is the combination ofthe following seemingly disparate observations in animals into aunifying pathway (the “Circle Hypothesis”) that provides a mechanisticbasis by which androgens dampen or down-modulate chronic pain in humans.FIGS. 3A-3B show the hypothesized metabolic pathway for testosterone inrelation to nociception in the central nervous system. FIG. 3A depictsthe pathway in normal individuals. Overview of Circle Hypothesis in thehealthy state: A painful stimulus, state of stress, or trauma issignaled by an increase in Substance P. Pain, stress or trauma alsocauses serotonin levels (and other stress-mediating neurochemicals thathelp regulate the descending control of pain (M. J. Millan, Progress inNeurobiology, 2002 66:355-474) to drop or be altered. This results in aloss of feeling of well-being. Substance P has been found to stimulatethe enzyme aromatase within the central nervous system nociceptive relayneurons in a highly regulated process that is mediated by proteinkinases and phosphoprotein phosphatases, which phosphorylate andde-phosphorylate aromatase (respectively), consistent with their statusas classic “gate-keeper” regulators of cell function. Aromatase isthereby stimulated to act upon its substrate testosterone, which can beprovided from the periphery and can cross the blood-brain barrier (BBB)for this purpose (also a highly regulated process, see elsewhereherein), to convert it to 17-beta estradiol within the dorsal horn ofthe spinal cord in the CNS. Increases in 17-beta estradiol cause thesubsequent upregulation of mRNA encoding enkephalins (opioid peptides)in the spinal cord dorsal horn nociceptive relay neurons. These opioidpeptides can both down-regulate Substance P (Zachariou et al., Euro. J.Pharmacol., 1997, 323:159-165), as well as dampen pain and bringstressor states toward healthy baseline states (eustress). The decreasein Substance P, along with concomitant increase in serotonin levels,also helps dampen or “wind-down” pain and return to thepre-painful/stressful state or “homeostasis,” i.e., a feeling ofwell-being.

Aromatase is not only found in the nociceptive relay neurons in thespinal cord, but also in the brain and the periphery, where it can be acritically important player with respect to pain pathways at any ofthese sites. In addition, there are mechanisms that favor entry oftestosterone (over estrogen) from the periphery through the blood-brainbarrier into the central nervous system. These mechanisms involve, inpart, sex hormone binding globulin (SHBG) and the complex regulation ofaromatase and its substrate testosterone.

Overview of Circle Hypothesis in the androgen deficient or unhealthystate: FIG. 3B shows the same cycle in patients having chronic pain,which may be related to any of the stressors as defined in paragraphs[0011] and [0029]. Chronic inflammatory pain states or unresolvablestress or trauma can lead to a dys-equilibrium, or state of distress,which is not appropriately resolved in these patients. Thus, patientswith inadequate or too-low androgen/testosterone are predicted to have a“frustrated cycle” as follows: The pain processing pathways above,pathways that normally resolve pain and return the patient to a healthystate (eustress), now unremittingly utilize testosterone that hastransited across the BBB into the CNS from the periphery, ultimatelyresulting in testosterone exhaustion within the spinal cord dorsal hornnociceptive relay neuron. As above, Substance P, acting as a signal forpain or stress, stimulates aromatase within the dorsal horn. However,because testosterone has been exhausted and depleted, the aromataseenzyme has no available substrate, and thus, aromatase is involved in a“frustrated cycle,” being unable to convert testosterone to 17-betaestradiol. Further, because testosterone has been depleted and 17-betaestradiol is not expressed, opioid peptides (enkephalins) are notup-regulated, and the opiate-mediated dampening of nociceptive signalsfails to occur, resulting in abnormal, chronic, ever-widening anddiffuse pain “wind-up” phenomena. The frustrated cycle results in therepetitive action of nociceptive C-fibers, augmented pain, andhyperalgesia, i.e., hypersensitivity to pain and a decreased thresholdto pain. Substance P remains elevated, serotonin remains reduced, and apatient will remain in a hypersensitive pain state, or at high risk ofpain with an abnormally low threshold for pain, with a lack of feelingof well-being, until the pain processing cycle is restored, for example,via androgen or testosterone replacement therapy. In summary, chronicpain can exhaust testosterone, the cycle is frustrated, and pain is notappropriately processed. The insufficient testosterone levels fail tomediate recovery from a painful stimulus, inflammatory pain, a stressor,or a state of trauma, resulting in a new dys-equilibrium or state ofdistress, that, in time, sets up altered neuronal circuitry or patternsthrough a process called neuronal plasticity, thereby allowing thedistressed state to become entrenched.

Essentially, this is consistent with a mechanism by which enkephalins,endorphins, and other opioid peptide molecules stimulate inhibitoryreceptors on nociceptive relay neurons. In turn, release of excitatoryeffectors, such as Substance P, is inhibited, with the inhibitoryreceptors in a location next to where the excitatory effectors arereleased (Zachariou et al., Euro. J. Pharmacol., 1997, 323:159-165).While others have contributed knowledge toward these concepts,particularly in animals, testosterone therapy has not yet been used forall the diverse types of chronic inflammatory pain seen in the clinic,pain which may be resistant to current common and standard paintherapeutics.

Details of the Circle Hypothesis. It is known that Substance P, actingas neurotransmitter, can transmit painful impulses along the ascendingpain pathways within the CNS. (Foldes, 1991 Anaesthesiol. Reanimat.,2005, 16:287-298; Siemion et al., Amino Acids, 2005, 29:161-176).Substance P is also a marker of inflammation. Thus, Substance P allowscommunication between the immune and neuroendocrine systems, and withinthe nervous system between the periphery and CNS, to mediate nociceptivesignaling. It is known that the sex steroid hormones can induce opioidpeptides within the spinal cord dorsal horn, and further, that opioidpeptides can inhibit Substance P (Zachariou et al., Eur. J. Pharmacol.,1997, 323:159-165). This invention relates to underlying causes ofchronic pain states, and likely relates to individuals who experience astressful event either 1) at a time when their sex steroid hormoneconcentrations are too low to properly attenuate pain signals, or 2) thestressor itself has exhausted the testosterone, either of which resultsin a failure to appropriately down-modulate nociceptive relay signalsand dampen wind-up pain phenomena. Both of our patient types, patientswith chronic unresolvable inflammatory pain, and distressed patientswith abnormally low pain thresholds, can be understood in the context ofthis “Circle Hypothesis.”

Substance P (P stands for “powder,” as it was discovered in a driedacetone powder of a neural tissue extract) is one of several neurokininpeptides, which are also known as tachykinin neuropeptides. Thesepeptides are generally from about ten to about 12 amino acids in length,and function to excite neurons, evoke behavioral responses, and tocontract smooth muscles. In addition, these peptides are potentvasodilators. In humans, neurokinins are encoded by two tachykinin genesTAC1 and TAC3. TAC1 encodes neurokinin A (previously known as SubstanceK), neuropeptide K (also known as neurokinin K), neuropeptide gamma andSubstance P. The different splice forms of the TACT gene result in theproduction of the different neurokinins. The TAC3 gene encodesneurokinin B. As described above, Substance P is involved innociception, transmitting painful inflammatory insults and informationabout tissue damage from peripheral receptors to the CNS, and as such,it is a well-known marker for inflammation. It functions as both aneurotransmitter and a neuromodulator.

The thymus may also play a role in chronic inflammatory pain. The thymusis known as a “primary lymphatic organ” responsible for maturing anddeveloping or “educating” thymic cells so they can emigrate toperipheral tissues and respond to “danger,” distress, pathogens, etc.,that assail the host. Thymic T cells are a major component and drivingforce in inflammatory responses, responding to the dangers that areperceived by the immune system. These lymphocytes are tightly regulatedin a bi-phasic way such that they initially proliferate (expansionphase) in response to disease such as infection. Once the insult iscleared and the immune system no longer perceives danger, thoseresponding T cells go through a contraction phase and are down-regulatedor programmed to die in order to re-establish a quiescent level(“eustress”). Chronic inflammatory pain states involve an out-of-balanceand undampened expansion of immune cells, an environment of inflammationthat can be autoimmune-like, and a failure to return to a quiescentnon-inflammatory state, resulting in pain, soreness and inflammationthat is not appropriately resolved (“distress”). Common markersassociated with chronic inflammatory pain states include, but are notlimited to, Substance P, elevated erythrocyte sedimentation rate, andelevated C-reactive protein or CRP (see paragraph [0029]). Gonadalsteroid hormones can act to dampen inflammatory cells (see paragraph[0014]), and concomitant with this, the conversion of testosterone toestrogen by aromatase within the CNS dampens nociception in the dorsalhorn nociceptive relay neuron. This pain signaling down-modulationlikely occurs within the CNS descending pathways of nociceptive relayneurons to resolve pain. For a general review of descending neuralpathways from cerebral structures to the dorsal horn of the spinal cordthat control pain (see Millan, M. J. “Descending control of pain”,Progress in Neurobiology, 2002, 66:355-474). The instant inventioninvolves raising serum levels of testosterone to higher levels, levelsthat are safe within the reference range and clinically effective, andthat can down-modulate inflammatory pain signaling and alleviate fatiguesuch that a healthy quiescent state (eustress) is promoted with feelingsof well-being.

Sources of endogenous androgens and the role of the HPA/HPO axis indistress. The chronic stress that induces adrenal hyporesponsiveness mayalso further decrease androgen production by the adrenal gland. Theadrenal gland accounts for approximately 25% of circulating testosteroneconcentrations in normal individuals, with an additional 25% from thegonads (post-menopausal ovaries normally continue to produce someandrogens) and 50% from prehormones, primarily androstenedione, derivedfrom both the adrenal gland and gonads. Sex steroid hormone productionhas been found to be exhausted and/or down-modulated in response tostress (Opstad, J. Clin. Endocrin. Metab., 1992 74(5):1176-1183) via theHPA (hypothalamus-pituitary-adrenal) axis in addition to the HPO(hypothalamus-pituitary-ovary/gonad) axis. Thus, adrenalhyporesponsiveness due to chronic stress could result in significantdecreases in testosterone production and could add to diminished gonadalfunction.

Chronic pain experienced by patients is thought to be related to adysfunctional stress response within the HPA axis, i.e., an exaggeratedACTH response and decreased cortisol response indicating adrenalhyporesponsiveness to the master stress hormone CRH (corticotropinreleasing hormone), that persists after the initiating event has beenresolved. Significantly elevated Substance P concentrations can be foundin the cerebrospinal fluid of all types of chronic inflammatory painpatients, which likely relates to increased pain signaling in thesepatients since, in the periphery, Substance P can induce mast celldegranulation and release of histamine which can directly excitenociceptive neurons (along with inflammatory immune cells) and amplifywind-up phenomena in chronic pain states.

A role for the sex steroid hormones in nociceptive pain processing. Datasupport a role for androgens and estrogens in opiate production in thenociceptive relay cells that transmit pain signals in the dorsal horn ofthe spinal cord, providing a mechanistic basis for testosteroneinvolvement in pain perception. This basis is likely related to “gatecontrol theory,” in which negative modulatory neurologic signalsdown-modulate nociceptive pain signals and restore the resting healthystate or homeostasis (the state of “eustress”). The loss of homeostasisdue to stressors (the state of “distress”) in chronic pain patients islikely exacerbated and driven by stress-induced exhaustion or catabolismof testosterone to the point of a testosterone deficient state. Neuronalplasticity, the ability of neuroendocrine pathways to enter into analtered set of equilibria that can be associated with pathology, called“allostasis” or “allostatic load,” according to Melzack (Pain Mechanism:A New Theory, Science, 1965, 150(3699):971-979) and others (or a stateof “distress,” according to Selye), then allows for hypersensitivity topain, amplification of pain, pain field widening (wind-up phenomena),such that a chronic pain state can become entrenched. The immune system,as well as neuronal-derived immunologic mediators of pain, frequentlycontribute to this pathology as well.

Combining the concept of stressors and stressor states and pain, withthe concept of androgen therapy to treat chronic inflammatory pain, is anovel and unique idea. Chronic inflammatory pain has many differentclinical manifestations and known causes. However, the importance ofstressor states has not been well understood, and has not beenaddressed, in the etiology of chronic inflammatory pain conditions. Inaddition, the consideration of a healthy sex steroid hormonal balance isnot standard practice within the pain clinic arena. A stressor state,whether acute or longstanding, takes a toll on a patient's systemicdefenses and compromises the hormonal balance, thereby influencing thepatient's painful condition.

Patients entering a stressor state, as described below, are at high riskfor chronic pain from two sources. First, if a subject manifests lowtestosterone, is borderline testosterone-deficient, or becomestestosterone-deficient, and if such a subject then enters a stressorstate, chronic pain can more readily occur. Thus, the subject is athigher risk and has greater susceptibility to pain states and clinical“distress” states. Second, if a subject with a painful condition,despite normal androgen levels initially, enters a stressor state, suchsubject's acute pain can become chronic pain due to androgen exhaustionand the development of an androgen-deficiency state. In both cases,androgen deficiency, and symptoms thereof, result in the failure ofopiates to be produced that would otherwise dampen nociceptive painrelay cells in the dorsal horn of the spinal cord and promote feelingsof well-being.

Evidence for the ability of stressors to cause androgen exhaustion canbe found in military personnel undergoing rigorous training. Opstad, (J.Clin. Endocrin. Metab., 1992, 74(5):1176-1183) discloses that personneltaking part in 5-day military endurance training courses that requirephysical activities on a round-the-clock basis show a decrease in theplasma levels of several androgenic compounds, including testosterone,dehydroepiandrosterone, androstenedione, as well as17α-hydroxyprogesterone. Plasma levels of these compounds can decreaseunder stress conditions by as much as 60% to 80%.

Preclinical animal studies are consistent with the concept thatandrogens can be important for dampening pain signaling via nociceptiverelay neurons in the spinal cord, but are not predictive of studies inhumans with chronic pain, unlike the present invention. Testosterone isknown to be important within the central nervous system in preclinicalstudies, although this has not translated into the clinic. Androgenreceptors can be widely found in specific patterns of expressionthroughout the CNS in various animal models. And testosteroneconcentrations have been shown to be dramatically decreased in the brainand spinal cord of rats in response to pain-inducing subcutaneousinjections of formalin into the paw. In these animals, the loss oftestosterone in the central nervous system was demonstrated to be due toits metabolism by 5α-reductase to dihydrotestosterone (Amini, H. et al.,Pharmacol. Biochem. Behay., 2002, 74:199-204). These authors pointed outthat dihydrotestosterone can be metabolized to5α-androstane-3α,17β-diol, which is an effective modulator of GABA_(A)receptor complexes in the brain. GABA_(A) receptors are found throughoutthe brain, and actions of GABA_(A) receptor modulators in the limbicsystem, specifically in the amygdala, are associated with feelings offear. The GABA_(A) receptor ion channel complex is an inhibitory ionchannel in the brain. Thus, testosterone may be relevant not only formodulation of pain but also for feelings of emotional well-being viabinding of its metabolites to the neurosteroid site of the GABA_(A)receptor, although this remains to be verified.

A cause-and-effect relationship between testosterone and pain sensationhas been suggested in animal models. For example, evidence supports theconcept that sex hormones can elevate the pain threshold in rodents, forexample, during pregnancy (Gintzler, A. R., Science, 1980, 210:193-195),when testosterone concentrations, as well as estrogen and progesteroneconcentrations, are elevated both in animal models and humans (Bammann,B. L. et al., Am. J. Obstet. Gynecol., 1980 137:293-298). However, theusage of androgens in humans to either dampen chronic inflammatory painor elevate an individual's pain threshold has not been considered ortested.

In other animal studies, aromatase-positive cells have been found in thespinal cord dorsal horn of higher vertebrates (quail), where initialprocessing of pain sensation occurs (Blomqvist, A., Compar. Neurol.,2000 423:549-551; Evrard, H. et al., J. Comparative Neurology, 2000,423:552-564). The presence of aromatase, which converts testosterone to17β-estradiol, is interesting because it is known that estrogen caninduce the transcription of opiates in estrogen receptor-positive cellsderived from the superficial layers of the spinal dorsal horn(Amandusson, A. et al., Neurosci. Lett., 1996 196:25-28; Amandusson, A.et al., Eur. J. Neurosci., 1996, 8:2440-2445; Amandusson, A. et al.,Pain, 1999 83:243-248), a location in the nociceptive pain relay neuronsthat is important for the synthesis of endogenous opiates.Administration of estrogen to ovariectomized female rats has beendemonstrated to increase spinal cord enkephalin transcription(Amandusson, A. et al., Pain, 1999, 83:243-248), and estrogenreceptor-positive cells co-localize with preproenkephalin mRNA(Amandusson, A. et al., Eur. J. Neurosci., 1996, 8:2440-2445). Theseendogenous opiates act on enkephalinergic neurons to mediate inhibitionof nociceptive relay cells, both in primary afferent fibers as well asin pain-modulating fibers descending from the brainstem (Ma, W. et al.,Neuroscience, 1997, 77:793-811). While there is good reason to think itis testosterone, rather than estrogen, that is more important fordampening pain, due in part to differential regulation by SHBG (sexhormone binding globulin) of the ability of estrogen vs. androgens tocross the blood-brain barrier, an animal dosed with sufficient estrogenmay still have a reduction in pain. However, estrogen orestrogen-progestin hormone replacement therapy (HRT) in women is notknown to be particularly effective with respect to beinganti-nociceptive. Thus, androgens, rather than estrogens, appear to bethe relevant hormone for effective migration from the periphery into theCNS to dampen pain.

Further evidence for the importance of androgens in dampening pain isfound in studies where gonadectomy of male and female rats has resultedin increased pain responses (i.e., a lower pain threshold) to theformalin test (with verified decreased testosterone and increasedestradiol plasma levels in male rats). Conversely, treatment withtestosterone has resulted in decreased pain responses concomitant withincreased testosterone plasma levels. Furthermore, exposure of femalemice to testosterone just after birth induces pharmacologically definedpatterns of analgesia in adults that are similar to male pathways. In atleast two studies, however, male or female gonadectomy resulted inimproved analgesia in rats (Nayebi and Ahmadiani, Pharmacol. Biochem.Behay., 1999, 64:467-71; Stoffel et al., J. Pain, 2005, 6(4):261-274).The fact that these in vivo animal study results are disparate showsthat the preclinical experiments and animal models discussed above,while suggestive, are not predictive of efficacy or safety in humansubjects. Therefore, it is desirable to be able to directly assess theability of androgen therapy to dampen pain in humans. Further, it isdesirable to be able to use androgen therapy in the treatment of chronicpain conditions. Confounders of age, and additional facets of sexualdimorphism relating to gender differences between males and females indevelopment and otherwise in relation to pain processing point to theunpredictable nature of chronic pain treatment in humans. In summary,while preclinical animal model experiments suggest the concept thattestosterone, or other androgens, may down-modulate pain in adult malesand females, the inventor has unexpectedly found that androgens can beused to successfully treat chronic pain in humans.

Chronic opioid usage can lower testosterone levels due to suppression ofthe HPG (Hypothalamic Pituitary Gonadal) Axis. Preclinical animalstudies that demonstrate an effect on nociception in gonadectomized rats(despite mixed and complex findings), have led clinical pain specialiststo look at the apparent side effects of androgen deficiency symptomsassociated with long term opioid usage in their chronic pain patients.So, for these patients, not only is chronic opioid usage known toexacerbate or worsen pain sensitivity (demonstrating the complexity ofopioids and their relationship to pain), but chronic opioidtherapy-associated androgen-like deficiency symptoms is thought to occurvia opioid down-regulation of the HPG axis, primarily through thesuppression of gonadotropin-releasing hormone (GnRH), which can resultin decreased production of the sex steroid hormones, includingtestosterone (for example, Abs et al., J. of Clin. Endocrinol. Metab.,2002, 85(6):2215-2222). The ability to assign cause and effect withrespect to the interplay between sex steroid hormones and nociception,and the ability to provide a comprehensive and logical mechanism,however, remains elusive.

Along these lines, it is relevant to uncover the flawed assumptionsunder which clinicians, who contemplate testosterone replacement therapyin patients on maintenance opioid treatment, view the role oftestosterone. Tennant et al. discloses four chronic pain subjectsalready on maintenance opioids as primary therapy for chronic pain, whowere given adjunctive testosterone therapy to try to improve thewell-being of these patients (“Testosterone Replacement in Chronic PainPatients,” Practical Pain Management, 2010, 12-15). In each of thesesubjects, testosterone (always as the adjunctive therapy in combinationwith primary opioid therapy) anecdotally and purportedly, resulted in animproved quality of life. However, it is difficult to draw anyconclusions from the study since 1) the study consisted of only fourpatients, 2) there were no uniform inclusion/exclusion criteria, 3)there was no control group, 4) no statistical analysis was performed, 5)statistical significance was not demonstrated, 6) testosterone was nottested as a primary therapy by itself, i.e., without opioids, 7) the endpoint studied was only changes in quality of life, 8) pain was nottested as an end point, and 9) the additional drugs and/or hormonesadministered to the patients in combination with the opioid-testosteronecombination therapy confounded any results that might have been seen.

Tennant advances an entirely different mechanism from the instantapplication. Even if Tennant's anecdotal reports could be consideredmeaningful, Tennant never suggested or considered that testosterone, byitself or as a primary therapy, was a treatment for pain, thattestosterone might have a direct effect on pain, or that testosteronemight have analgesic properties by itself. As for a possible mechanism,Tennant hypothesized that any analgesic effect would be from theexogenous opioids. Since Tennant never considered that testosterone canact directly on nociception, he never tested testosterone alone as aprimary therapy with or without opioid treatment. Tennant believed thattestosterone aided the activity of the primary therapy opioids byimproving the binding of opioid peptides to their opioid receptors. InTennant's mind, a study of testosterone alone would make no sense sincetestosterone could have an effect only in combination treatment with theprimary therapy exogenous opioids to augment their pharmacologic effect.

Daniell cited the same studies as those cited by Tennant and concludedsimilarly that anti-nociception would be mediated by exogenous opioids,not testosterone, and that testosterone replacement therapy was actingto alleviate non pain symptoms in patients on maintenance opioidtherapy. Daniell et al. carried out an open-label study (withoutplacebo) in males on maintenance or primary opioid therapy to determineif adjunctive testosterone therapy could reverse the non-pain symptomsof testosterone deficiency, including sexual function, mood anddepression (Daniell et al., “Open-label pilot study of testosteronepatch therapy in men with opioid-induced androgen deficiency,” J. Pain,2006, 7(3):200-210). Pain was assessed to determine if the action of theopioids as primary therapy could be improved, but no significant changewas found in the pain severity score. Daniell concluded that “It isdifficult to interpret these findings in the absence of a placebogroup.”

How the instant invention differs from Tennant and from Daniell. Thebasis for both Tennant's and Daniell's reasoning, including anexplanation of the flaws in their reasoning, is as follows: 1) Stoffelet al. carried out a study in rats in which gonadectomy sometimesdecreased, and sex steroid hormones sometimes increased, opioid receptoragonist-induced anti-nociception (Stoffel et al., J. Pain, 2005,6(4):261-274). However, Stoffel actually concluded that because theeffects were so variable, sex hormone influence on opioid analgesia wasnot likely to be an effect of sex hormones on nociception, but instead“might be more readily explained by organizational effects of gonadalsteroids” on opioid receptors. This type of variable data, both in maleand female animals, in which gonadectomy can increase (rather thandecrease) pain thresholds, has also been confirmed by others (see, e.g.,Nayebi and Ahmandiani, Pharmacol. Biochem. Behay., 1999, 64:467-471). 2)Tennant incorrectly cites a study by Holaday et al. as evidence for arelationship between testosterone and opioids (J. Pharmacol. Exp.Therapeut., 1979, 208(2):176-183). The Holaday study does support aninterplay between glucocorticoids and opioids, but there is no mentionor contemplation of an interplay between the sex steroid hormones andopioids. 3) Tennant incorrectly cites a study by Long and Holaday asevidence that testosterone improves transport of opioids across theblood-brain barrier (Science, 1985, 227:1580-1583). In reality, Long andHoladay provide evidence that adrenal-cortex function (via adrenalectomyvs. adrenal demedullation, and corticosterone (glucocorticoid)replacement) modulates the permeability of brain tissue to isotopicallylabeled BSA. Sex steroid hormones, quite different functionally fromglucocorticoids (although both are produced in the adrenal cortex), arenot mentioned or contemplated in the Long and Holaday study. Unlike theinstant invention, Tennant and Daniell both fail to consider thepossibility that the relevant mechanism with respect to the blood-brainbarrier and its relationship with nociception might be the regulation bysex hormone binding globulin (SHBG) of testosterone transiting acrossthe BBB, for usage as the substrate for aromatase within the dorsal hornof the nociceptive relay neuron (for which there is evidence, see, e.g.,MacLusky et al., Science, 1981, 211:1294-1303). 4) Both Tennant andDaniell assess androgen replacement therapy as an adjunctive therapy inchronic pain patients on primary therapy maintenance opioids by lookingfor improvement of testosterone deficiency symptoms, and the symptomslisted do not include pain, other than that mediated by the primaryopioid therapeutics, an indication that neither Tennant nor Daniellconsider testosterone's mechanism of action to be pain related. Rather,testosterone is evaluated as an adjunctive therapy both by Tennant (seeTable 3) and Daniell for improving non-pain quality of life symptoms

In conclusion, it has been recognized for some time that various drugsand treatments, including opioids and anti-depressants, can have theside effect of decreasing testosterone levels. Unlike the instantinvention, however, those of skill have never considered taking thisconcept further to the next step, that treating a chronic pain patientwith testosterone as a primary therapy or alone, without opioids, cansafely, statistically and significantly improve pain symptoms viatestosterone's ability to upregulate endogenous opioid peptides withinthe nociceptive neurons in the spinal cord (Circle Hypothesis)—withoutthe morbidities and side effects of primary therapy with exogenousopioids. Nor has anyone provided a comprehensive and logical mechanismby which this happens, unlike the instant invention, which providesdetailed, strong evidence for the biologic pathways underlyingtestosterone's ability to act directly, in the absence of exogenousopiates, as an anti-nociceptive pain therapeutic in humans.

The invention relates to a method of reducing inflammatory pain orameliorating a clinical state of “distress” in a patient with symptomsof androgen deficiency and/or with an abnormally low pain threshold (andconsequently a high susceptibility or risk of having a chronicinflammatory pain state): Overview. The invention relates to a method ofreducing inflammatory pain or a clinical state of distress, as describedin paragraph [0029] for example, in an androgen-deficient human subjectcomprising diagnosing a human subject to have at least one of theindications defined above in paragraphs [0029] or [0041]; determining ifthe subject has serum androgen levels in the lower half of theappropriate reference range; and if the subject has at least one of oneof the indications defined above in paragraphs [0029] and [0041], alongwith androgen levels in the lower half of the appropriate referencerange; administering, as primary therapy, a composition comprising apain-reducing amount of an androgen to human subject having symptoms ofandrogen deficiency, wherein pain is reduced safely and effectively. Theinvention also contemplates the administration of a compositionconsisting essentially of a pain-reducing amount of an androgen to ahuman subject having symptoms of androgen deficiency, wherein pain isreduced safely and effectively.

For each of the following embodiments of the invention the term“elevated” means at the high end or above the normal or reference rangeof values for the measured statistic, the measured statistic including,but not limited to, C-reactive protein, erythrocyte sedimentation rate,or Substance P levels. The term “decreased” means below or at the lowend of the normal or reference range of values for the measuredstatistic, the measured statistic including, but not limited to, thelevels of endogenous opioid peptides.

The invention relates to methods of reducing chronic inflammatory painin a human subject. Specifically, the invention relates to a method ofreducing chronic inflammatory pain in a human subject with androgendeficiency symptoms comprising diagnosing a human subject to have atleast one of a) elevated C-reactive protein, b) elevated erythrocytesedimentation rate, c) DSM-IV disorder 307.80, d) DSM-IV disorder307.89, or e) an unresolved stressor state; determining if the subjecthas androgen levels in the lower half of the appropriate referencerange. If the subject has at least one of a) elevated C-reactiveprotein, b) elevated erythrocyte sedimentation rate, c) DSM-IV disorder307.80, d) DSM-IV disorder 307.89, or e) an unresolved stressor state,along with androgen levels in the lower half of the appropriatereference range; the method includes administering a compositioncomprising a pain-reducing amount of an androgen to the human subjectwith androgen deficiency symptoms, wherein pain is reduced safely andeffectively. This embodiment of the invention also contemplates theadministration of a composition consisting essentially of apain-reducing amount of an androgen to a human subject having symptomsof androgen deficiency, wherein the subject's pain is reduced safely andeffectively.

Alternatively, the invention relates to a method of reducing chronicinflammatory pain in a human subject with androgen deficiency symptomsconsisting essentially of diagnosing a human subject to have at leastone of a) elevated C-reactive protein, b) elevated erythrocytesedimentation rate, c) DSM-IV disorder 307.80, d) DSM-IV disorder307.89, or e) an unresolved stressor state; determining if the subjecthas androgen levels in the lower half of the appropriate referencerange. If the subject has at least one of a) elevated C-reactiveprotein, b) elevated erythrocyte sedimentation rate, c) DSM-IV disorder307.80, d) DSM-IV disorder 307.89, or e) an unresolved stressor state,along with androgen levels in the lower half of the appropriatereference range; the method includes administering a compositioncomprising a pain-reducing amount of an androgen to the human subjectwith androgen deficiency symptoms, wherein pain is reduced safely andeffectively. This embodiment of the invention also contemplates theadministration of a composition consisting essentially of apain-reducing amount of an androgen to a human subject having symptomsof androgen deficiency, wherein the subject's pain is reduced safely andeffectively.

The invention relates to methods of increasing the pain threshold in ahuman subject. The invention also relates to a method of increasing thepain threshold of an androgen-deficient human subject comprisingdiagnosing a human subject to have at least one of the indicationsdefined above in paragraphs [0029] and [0041]; determining if thesubject has androgen levels in the lower half of the appropriatereference range; and, if the subject has at least one of the indicationsdefined above in paragraphs [0029] and [0041] such as having anunresolvable state of distress, along with androgen levels in the lowerhalf of the appropriate reference range; administering a compositioncomprising an androgen as primary therapy to human subject havingsymptoms of androgen deficiency, wherein the subject's pain-threshold isincreased safely and effectively. This embodiment of the invention alsocontemplates the administration of a composition consisting essentiallyof a pain threshold increasing amount of an androgen to a human subjecthaving symptoms of androgen deficiency, wherein the subject's painthreshold is increased safely and effectively

Alternatively, the invention relates to a method of increasing the painthreshold of an androgen-deficient human subject consisting essentiallyof diagnosing a human subject to have at least one of a) elevatedC-reactive protein, b) elevated erythrocyte sedimentation rate, c)DSM-IV disorder 307.80, d) DSM-IV disorder 307.89, or e) an unresolvedstressor state; determining if the subject has androgen levels in thelower half of the appropriate reference range. If the subject has atleast one of a) elevated C-reactive protein, b) elevated erythrocytesedimentation rate, c) DSM-IV disorder 307.80, d) DSM-IV disorder307.89, or e) an unresolved stressor state, along with androgen levelsin the lower half of the appropriate reference range, the methodincludes administering a composition comprising a pain-thresholdincreasing amount of an androgen to a human subject with androgendeficiency, wherein the subject's pain threshold is increased safely andeffectively. This embodiment of the invention also contemplates theadministration of a composition consisting essentially of a painthreshold increasing amount of an androgen to a human subject havingsymptoms of androgen deficiency, wherein the subject's pain threshold isincreased safely and effectively

The invention relates to method of testing if a human subject wouldbenefit from androgen administration. The invention further relates to amethod for determining if a human subject would benefit from androgenadministration comprising testing for at least one of the indicationsdefined above in paragraphs [0029] and [0041]; determining if thesubject has androgen levels in the lower half of the appropriatereference range; testing the subject's pain threshold; and if thesubject has at least one of the indications defined above in paragraphs[0029] and [0041], along with androgen levels in the lower half of theappropriate reference range and a low threshold of pain, administering acomposition comprising an androgen to the subject as the primary therapyfor pain treatment, wherein the subject's androgen serum levels arerestored safely and effectively to the middle-upper range of anappropriate reference range. This embodiment of the invention alsocontemplates the administration of a composition consisting essentiallyof an androgen to the subject, wherein the subject's androgen serumlevels are restored safely and effectively to the middle-upper range ofthe appropriate reference range.

Alternatively, the invention relates to a method for determining if ahuman subject would benefit from androgen administration consistingessentially of testing for at least one of a) elevated C-reactiveprotein, b) elevated erythrocyte sedimentation rate, c) DSM-IV disorder307.80, d) DSM-IV disorder 307.89, or e) an unresolved stressor state;determining if the subject has androgen levels in the lower half of theappropriate reference range; testing the subject's pain threshold. Ifthe subject has at least one of a) elevated C-reactive protein, b)elevated erythrocyte sedimentation rate, c) DSM-IV disorder 307.80, d)DSM-IV disorder 307.89, or e) an unresolved stressor state, along withandrogen in the lower half of the appropriate reference range, and ifthe subject has androgen levels in the lower half of the appropriatereference range and a low threshold of pain, the subject would be acandidate for androgen therapy. This embodiment of the inventioncontemplates the administration of a composition either comprising orconsisting essentially of a pain threshold increasing amount of anandrogen to a human subject having symptoms of androgen deficiency,wherein the subject's androgen serum levels are restored safely andeffectively to the middle-upper range of the appropriate referencerange.

Doctor's diagnostic kit for patient selection. The invention alsorelates to a kit for determining if a human subject would benefit fromandrogen administration as a primary therapy comprising instructions fordiagnosing a subject as having an androgen-deficiency related disorderthat is treatable by administration of a composition comprising anandrogen or by administration of a composition consisting essentially ofan androgen. The instructions can comprise instructing a health careprovider how to test the subject's androgen serum levels and how todetermine if the subject has at least one of the indications definedabove in paragraphs [0029] and [0041]. The instructions can furthercomprise instructing the health care provider how to testing thesubject's pain threshold; and instructing the health care provider toadminister an androgen to the subject if the subject has androgen levelsin the lower half of the appropriate reference range, a low threshold ofpain, and at least one of the indications defined above in paragraphs[0029] and [0041]; so that the subject's androgen serum levels arerestored safely and effectively to the middle-upper portion of theappropriate reference range. The instructions can further direct thehealth care provider to exclude patients receiving exogenous opioidtherapy or include such opioid therapy as an adjunctive, rather thanprimary, therapy.

Selection of patients. Patients will be selected based on 1) theirtestosterone serum levels being in the lower half of the referencerange, concomitant with at least one of the following: 2a) the presenceof chronic or acute unresolved pain (pain assessment as definedelsewhere in this application), and/or 2b) the lack of a feeling ofwell-being combined with a low threshold of pain (threshold testing asdefined elsewhere in this application), and/or 2c) a failure to adapt toor resolve stress (stressors as defined in this application as amaladaptive and unresolved state of “distress”). A medical doctor caneither 1) use a diagnostic kit for patient selection, or 2) continue thetreatment of someone already diagnosed as having testosterone serumlevels in the lower half of the reference range, and with unresolvedpain or distress or abnormally low pain threshold, such thatcontinuation treatment is independent of the diagnostic kit for patientselection.

To aid doctors in assessing an individual for treatment, they mayconsider the symptoms of androgen deficiency. An androgen-deficientsubject generally will exhibit a variety of symptoms, including, but notlimited to, unresolvable pain, a loss of a feeling of well-being, hotflashes, sweating, insomnia, nervousness, irritability, tiredness, lossof motivation, short-term memory problems, declining self-esteem,depression, decreased energy levels, decline or loss of libido,diminished muscle mass, hair loss, abdominal obesity, (see paragraphs[0008] and [0040]). In men, a reduced volume of semen and poor erectilefunction can be symptoms of androgen deficiency. The subjects thatreceive primary androgen treatment may or may not also be receivingconcurrent adjunctive administration of an exogenous opioid. As usedherein, the term “concurrently” means sufficiently close in time toproduce a combined effect (that is, concurrently may be simultaneously,or it may be two or more events occurring within a short time periodbefore or after each other).

Alternatively, the invention relates to a kit for determining if a humansubject would benefit from androgen administration comprisinginstructions for diagnosing a subject as having symptoms of anandrogen-deficiency treatable by administration of an androgen. Theinstructions consist essentially of instructing a health care providerhow to test the subject's androgen serum levels; instructing the healthcare provider to determine if the subject has at least one of a)elevated C-reactive protein, b) elevated erythrocyte sedimentation rate,c) DSM-IV disorder 307.80, d) DSM-IV disorder 307.89, or e) anunresolved stressor state; instructing the health care provider how totest the subject's pain threshold; and instructing the health careprovider to administer a composition either comprising or consistingessentially of an androgen to the subject if the subject has androgenlevels in the lower portion of the of the appropriate reference range,has a low threshold of pain, and at least one of a) elevated C-reactiveprotein, b) elevated erythrocyte sedimentation rate, c) DSM-IV disorder307.80, d) DSM-IV disorder 307.89, or e) an unresolved stressor state;so that the subject's androgen serum levels are restored to themiddle-upper range of an appropriate reference range.

Administration of testosterone can increase the level of endogenousopioid peptides. The invention also relates to a method of increasingendogenous opioid peptide production an androgen-deficient, opioidpeptide-deficient human subject comprising: diagnosing a human subjectto have at least one of a) elevated C-reactive protein, b) elevatederythrocyte sedimentation rate, c) DSM-IV disorder 307.80, d) DSM-IVdisorder 307.89, or e) an unresolved stressor state; determining if thesubject has androgen levels in the lower half of the appropriatereference range; determining if the subject low endogenous opioidpeptide levels; and, if the subject has at least one of a) elevatedC-reactive protein, b) elevated erythrocyte sedimentation rate, c)DSM-IV disorder 307.80, d) DSM-IV disorder 307.89, or e) an unresolvedstressor state, along with androgen levels in the lower half of theappropriate reference range and low endogenous opioid peptide levels;administering a composition comprising an androgen to a human subjectwith androgen and endogenous opioid peptide deficiencies, wherein thesubject's production of endogenous opioid peptides is increased. Thelevel of a subject's endogenous opioid peptides can be measured incerebrospinal fluid, however, one of ordinary skill in the art wouldknow how to test for endogenous opioid peptides at other sitesincluding, but not limited to, the periphery. Further, one of skill inthe art might also test for other indicators of pain or efficacy in thecerebrospinal fluid. This embodiment of the invention also contemplatesthe administration of a composition consisting essentially of anendogenous opioid peptide-increasing amount of an androgen to a humansubject having symptoms of androgen deficiency, wherein the subject'slevels of endogenous opioid peptides are increased safely andeffectively

Alternatively, the invention relates to a method of increasingendogenous opioid peptide production an androgen-deficient, endogenousopioid peptide deficient human subject consisting essentially ofdiagnosing a human subject to have at least one of a) elevatedC-reactive protein, b) elevated erythrocyte sedimentation rate, c)DSM-IV disorder 307.80, d) DSM-IV disorder 307.89, or e) an unresolvedstressor state; determining if the subject has androgen levels in thelower half of the appropriate reference range; determining if thesubject has low endogenous opioid peptide levels. If the subject has atleast one of a) elevated C-reactive protein, b) elevated erythrocytesedimentation rate, c) DSM-IV disorder 307.80, d) DSM-IV disorder307.89, or e) an unresolved stressor state, along with androgen levelsin the lower half of the appropriate reference range and low endogenousopioid peptide levels; the method includes administering a compositioncomprising an androgen to a human subject with androgen and opioidpeptide deficiencies, wherein the subject's production of endogenousopioid peptides is increased. This embodiment of the invention alsocontemplates the administration of a composition consisting essentiallyof an endogenous opioid peptide-increasing amount of an androgen to ahuman subject having symptoms of androgen deficiency, wherein thesubject's levels of endogenous opioid peptides are increased safely andeffectively

Opioid peptides are a class of peptide molecules that function asneurotransmitters. Endogenous opioid peptides can be produced at siteswithin the central nervous system, including but not limited to, thepituitary gland, the hypothalamus, and the spinal cord. Endogenousopioid peptides can also be produced within the periphery. Theseendogenous opioid peptides resemble exogenous opioid compounds in theiractions. The opioid peptides that can be used in the instant inventioninclude, but are not limited to enkephalins. endorphins, dynorphins,adrenorphhin, amidorphin, and opiorphin. Each of these subgroups ofopioid peptides also has several members. For example, the endorphinsinclude, but are not limited to, alpha-endorphin, beta-endorphin andgamma-endorphin. Enkephalins include but are not limited to, the activeforms of enkephalin ala(2)-MePhe(4)-Gly(5), enkephalinD-Penicillamine(2,5), enkephalin leucine, and enkephalin methionine.Other opioid peptides include prooiomelanocortin (POMC), the gene forwhich codes for beta-endorphin and gamma-endorphin. As with exogenousopioid compounds, the endogenous opioid peptides bind to opioidreceptors to exert their action. Pharmacological studies have shown thatthere are several subtypes of opioid receptors to which the opioidpeptides can bind. For example, mu1, mu2, kappa1, kappa2, delta1, delta2opioid receptors are among those that have been studied. Opioidpeptides, as defined herein, include those opioid peptides that bind tothese opioid receptors and thereby mediate pharmacologic activity.

For each of the above embodiments of the present invention, additionalparameters can be determined. For example, one measurement of anindication that can be treated using an androgen composition includesmeasuring the level of a subject's endogenous opioid peptides, and ifthey are decreased below the normal level or reference range, thesubject may be a candidate for treatment, if the other conditions ofandrogen deficiency or symptoms thereof are met. Another indication thatcan be measured is Substance P, and if the subject's Substance P levelis increased above the normal level, the subject may be a candidate fortreatment, if the other conditions of androgen deficiency or symptomsthereof are met.

In accordance with the invention, androgen therapy is the primarytherapy to be administered for all of the above embodiments of theinvention. Further, in accordance with the invention, subjects receivingprimary androgen therapy may also receive adjunctive opioid therapy ifthey have exogenous opioid-induced hypogonadism or other conditions thatmight require such adjunctive opioid therapy in addition to the primaryandrogen therapy. Further, while androgens remain the primary therapyfor the methods of the invention, other compounds, such as, but notlimited to, antidepressants may also be administered as adjunctivetherapies.

Thus, using all of the above parameters, one of skill in the art candesign and implement a “personalized” treatment program for subjects inneed of pain reduction or an increase in their pain threshold.Specifically, one or more kits can be designed to measure and/or testfor the levels of a variety of metabolic functions and/or compounds thatare important for such functions. For example, not only can the serumlevels of androgens, such as, but not limited to, testosterone, bedetermined, but the level and activity of enzymes that catabolizeandrogens can be determined. Endogenous opioid peptides, such asenkephalins, can be measured, as can Substance P, an important markerfor inflammatory pain. By determining the level of these variousmetabolic compounds and components, androgen therapy can be modulatedand adjusted, depending upon the needs of the specific patients. Theadjustment can depend upon the catabolic breakdown and saturation ofandrogens and their receptors. Further, by adjusting the level ofandrogen administered as a primary therapy, adjunctive therapies, suchas opioids or antidepressants can be adjusted downwards, thus avoidingsome of the detrimental side effects of these treatments. As anotherexample, a personalized medicine kit could consist of assessing theactivity of enzymes that catabolize testosterone and other endogenousandrogens, which could be assessed by targeted gene expression arrayprofiling of these enzymes to determine if an individual has highcatabolic activity, necessitating higher dosing of testosterone therapyfor efficacy, or low catabolic activity, necessitating lower dosing oftestosterone therapy for safety. Likewise, an individual can be testedfor endogenous enkephalins over time to determine whether thetestosterone dosing is sufficient (enkephalins are raised into thenormal range) or dosing needs to be increased (enkephalins have not yetbeen raised into the normal range). Substance P can be tested, and ifits level is decreased to a normal resting state, the testosterone dosecan be held constant, or even decreased if there are signs of androgenexcess; and if Substance P levels are not decreased, the testosteronedose can be increased to a safe level that is still within thetestosterone reference range. One of skill would know whether to testfor levels of these molecules in the spinal cord or the periphery, andwhether to test cerebrospinal fluid or serum.

Stress and pain are normally closely associated with immunologicmediators of pain. One method of determining the presence of chronicinflammatory pain, is the erythrocyte sedimentation rate, or “sed rate,”as described above. Patients with chronic inflammatory pain most oftenshow an elevated sed rate, which is demonstrative of the role ofimmunologic mediators. A second test for a chronic inflammatory painstate, the C-reactive protein test, can also be used to distinguishchronic inflammatory pain from non-inflammatory pain. Inflammatorystates will cause an increase in the level of C-reactive protein, whileconditions not related to an inflammatory component would remainunchanged. For purposes of selecting patients with chronic inflammatorypain for treatment, patients can be selected who have an abnormalerythrocyte sedimentation rate test result of >22 mm/hr for men or >29mm/hr for women, and/or an abnormal C-reactive protein test result of >3mg/dL, indicating the patient has inflammatory pain. In addition,Substance P, a neurokinin peptide, is also a marker for inflammatorypain. Thus testing a subject for the presence, absence, and/or level ofSubstance P is another method that can be used to diagnose a chronicinflammatory pain state.

For accruing female patients who are in the lower half of the referencerange, either total testosterone, free testosterone and/or bioavailabletestosterone can be considered. When considering total testosterone, the“lower half of the reference range for total testosterone” is defined asless than or equal to about 0.5 ng/mL when using the DSL totaltestosterone serum level assay; or less than or equal to about 0.4 ng/mLwhen using the Mayo Medical Labs total testosterone serum level assay(Table 1). A person of skill in the art would understand that he wouldbe able to use other equivalent assay tests to define and test for thelower half of the reference range.

For accruing male patients who are in the lower half of the referencerange, “lower half of the reference range for total testosterone” isdefined as less than or equal to about 6 ng/mL when using the MayoMedical Labs total testosterone serum level assay. If using another testwith its own reference range, a person of skill would assess patientaccrual serum level limits in an equivalent way for males vs. femalesusing the appropriate reference range.

The methods of administering androgen therapy. This invention relates toa method of treating a human subject with clinical symptoms of androgendeficiency, chronic inflammatory pain, or unresolvable states ofdistress (see paragraphs [0029] and [0041] above), whose serum levels ofandrogen are in the lower half of the appropriate reference range. Themethod is comprised of administering a composition comprising apain-reducing amount of an androgen to a human subject as the primarytherapy, such that the resultant serum levels are raised sufficientlyfor efficacy, but are not raised significantly above the upper end ofthe reference range. The invention further relates to a method ofincreasing the pain threshold of an androgen-deficient human subjectwith clinical symptoms of androgen deficiency, or unresolvable states ofdistress (see paragraphs [0029] and [0041] above), whose serum levels ofandrogen are in the lower half of the appropriate reference range,comprising administering a composition comprising a painthreshold-increasing amount of an androgen as the primary therapy, suchthat the resultant serum levels are raised sufficiently for efficacy,but are not raised significantly above the upper end of the referencerange. The administration can be on a daily basis, or any basisincluding, but not limited to, weekly or monthly, depending upon theindividual patient. The subject of the instant invention may be a femalesubject or a male subject. The pain to be treated can be caused by anumber of circumstances, and further exacerbated by additionalstressor(s) introduced into a subject's life. Further, a subject mayhave a chronic medical state accompanied by an additional stressorstate, that causes or exacerbates chronic pain. A stressor state,defined elsewhere herein, may sometimes be the cause of chronic pain ina subject, and/or the subject may be susceptible to stress/distress dueto too-low androgen levels. The composition can also consist essentiallyof an androgen. The androgen can be a biologically active androgen, andcan be administered by a variety of means, including, but not limitedto, transdermal administration, oral administration, buccaladministration, injection, implanted pellets, or suppository.

For example, in some instances (for both males and females) it will bedesirable to administer a first bolus dose of the androgen composition,after which a maintenance dose will be administered. The maintenancedose can be determined by measuring the serum androgen levels atpredetermined time points to ensure that steady state serum levels arereached and that these levels are maintained within the appropriatereference range. Should the serum androgen levels change over time, themaintenance dose can be altered accordingly. Alternatively, the androgencomposition can be administered as a once daily dose, or a divided dose.For example, the composition can be administered twice a day (e.g.,morning and evening), three times a day (e.g., with meals), or using anyother regimen. Again, the subject's serum androgen levels should reachsteady state, be maintained within the appropriate reference range, andcan be adjusted over time. Further, in each embodiment of the presentinvention it is desirable to measure a subject's androgen blood levelsat appropriate intervals while the subject is receiving androgentherapy. By doing so, it can be determined if steady state androgenserum levels are attained and the treatment is effective. Further, otherlonger acting methods of administration of the androgen composition canbe considered, including but not limited to, depot formulations,intramuscular injections, and subcutaneous injections, as described inparagraphs [0141]-[0145] below. Thus, the dose and/or dosing regimen canbe altered in the case of a change in a subject's health status (eitherpositive or negative), so as to re-attain the steady state and androgenserum levels within the appropriate reference range. Alternatively, thelevels of endogenous opioid peptides or Substance P can also bemonitored, and the dose and/or dosing regimen altered as necessary, toensure that the appropriate levels of endogenous opioid peptides orSubstance P are maintained.

In one embodiment of the invention, the biologically active androgen maybe a testosterone ester such as, but not limited to, testosteroneenanthate or testosterone cypionate. In another embodiment of theinvention, the bioactive androgen is testosterone. As described above,this is applicable to treating chronic pain in a subject and/or forincreasing the pain threshold in a subject.

The invention relates to a method of reducing chronic pain in a humansubject with symptoms of androgen deficiency, androgen-deficiency asdefined in paragraphs [0008], [0029]-[0033], and [0041], comprisingadministering a pain-reducing amount of an androgen as primary therapyto a human subject with symptoms of androgen deficiency, wherein pain isreduced safely and effectively. The subject can be suffering from acondition selected from the group consisting of chronic pain, and paincaused by a chronic stressor state, stressor state as defined inparagraphs [0011], [0029], and [0041]. The method also relates to amethod of increasing the pain threshold in an androgen-deficient humansubject comprising administering a pain-threshold-increasing amount ofan androgen as primary therapy to the subject, so that the subject'spain threshold is increased safely and effectively, as defined elsewhereherein.

In addition, the subject's androgen serum levels are restored to serumlevels at or below the upper end of the appropriate reference range asdefined by the mean of the upper end, plus or minus the standard errorof the mean, SEM. In some cases, even an androgen serum level slightlyabove the reference range is both safe and efficacious, with “safety”defined as being within the standard error of the mean of the upperlimit of the appropriate reference range and not causing clinicalsymptoms of androgen excess. Generally, the androgen used in theinvention is a bioactive androgen. Bioactive androgens may be active intheir native state, and/or may be a precursor or pro-drug that ismetabolized to a bioactive state upon delivery to the subject. Themethod encompasses the administration of a biologically active androgen,which may be, but is not limited to, testosterone, androstenedione,androstendiol, dehydroepiandrosterone, danazol, fluoxymesterone,oxandrolone, nandrolone decanoate, nandrolone phenpropionate,oxymethalone, stanozolol, methandrostenolone, testolactone,pregnenolone, dihydrotestosterone, methyltestosterone, bioactiveandrogen precursors, and testosterone esters. If a testosterone ester isadministered it may be, but is not limited to, testosterone enanthate ortestosterone cypionate. Testosterone can be the androgen employed by theinvention.

The methods of the invention can be practiced on both female and malesubjects. For female subjects, the bioactive androgen can betransdermally administered in a daily unit dose of about 0.1 mg to about12.8 mg of the androgen in a pharmaceutically acceptable carrierformulated for daily topical administration as a gel and wherein the gelis formulated to deliver steady state total androgen serum levelswithout raising free androgen serum levels or twenty-four hour freeandrogen AUC above the levels required for therapeutic efficacy andsafety.

For a male subject, the bioactive androgen can be transdermallyadministered in a daily unit dose of about 35 mg to about 100 mg of thebioactive androgen in a pharmaceutically acceptable carrier formulatedfor daily topical administration as a gel and wherein the gel isformulated to deliver steady state total androgen serum levels withoutraising free androgen serum levels or twenty-four hour free androgen AUCabove the levels required for therapeutic efficacy and safety. Thus,chronic pain is reduced and the serum levels of free testosterone can beraised to a level that is below or at the upper part of the referencerange (+/−SEM).

Androgens used in human studies—form and delivery. Most trials involvinghormone replacement therapy have used derivatives of hormones naturallyfound in women. These derivatized hormones have been promoted because oftheir patentability and their extended half-life. Androgens are noexception since the androgen hormone most prescribed for women has beenmethyltestosterone, where methylation at the C-17 position increases itsoral bioavailability. A subset of patients do not tolerate derivatizedhormones very well, however. Derivatized compounds are not metabolizednormally, and therefore may not be the best candidates forcommercialization. Non-derivatized exogenous hormones that arestructurally identical to endogenous hormones can have shortplasma/serum half-lives that range from 10-100 minutes, however, makingoral administration of native hormones problematic. To address theseissues, transdermal delivery systems have been developed fortestosterone, which provide sustained delivery while minimizing firstpass hepatotoxicity, which can be problematic with oral formulations ofpharmacotherapeutics. Further, for optimal patient tolerance,transdermal gel delivery also avoids the skin irritation many patientsexperience with repeated use of a transdermal patch delivery system.However, other forms of androgen delivery are available, each havingboth benefits and drawbacks.

Maintaining safety while administering androgen therapy by maintainingandrogen serum levels within the reference range. For females (ormales), administration of an androgen that achieves serum levels outsidethe reference range can be unsafe. The instantly claimed totaltestosterone level for females from about 0.9 ng/mL to about 1.4 ng/mL,is an extremely narrow range, even narrower than the reference range asshown in Table 1 below. Levels in excess of the instantly claimed rangecan cause, for example, hirsutism, acne, permanent changes in voice,emotional changes, and the more serious side effects of heart disease,cancer, and liver disease. Thus, it is important to maintain safety bykeeping testosterone serum blood levels within the reference range andavoiding clinical symptoms of androgen excess. And safety must becoupled with efficacy as demonstrated by significantly raisingtestosterone blood levels from baseline levels in the lower half of thereference range to the upper half of the reference range, whilesignificantly decreasing clinical symptoms of androgen deficiency.Examples of these changes and side effects are discussed below.

It is desirable to maintain a patient's androgen serum levels within themiddle to upper portion of the appropriate reference range. If androgensare administered in excess, clinical symptoms of androgen excess canappear. These symptoms can range from annoying to dangerous. Generally,the symptoms of androgen excess include, but are not limited to,excessive and abnormal hirsutism, increased anger, adverse lipidchanges, cardiovascular disease, abnormal liver function, weight gain,abnormal fat to muscle mass, acne, alteration of libido, edema,functional and structural liver damage, cancer, permanent changes invoice, emotional or mood changes, and diabetes.

For assessing safety, female patients will be dose-adjusted such thatthe “upper limit of the reference range for free testosterone” isdefined as less than or equal to about 3.3 pg/mL when using the DSL freetestosterone serum level assay (Table 1); and less than or equal toabout 19 pg/mL when using the Mayo Medical Labs free testosterone serumlevel assay. If using another test with its own reference range, aperson of skill would assess safety serum level limits in an equivalentway.

For assessing safety, male patients will be dose adjusted such that the“upper limit of the reference range for free testosterone” is defined asless than or equal to about 300 pg/mL when using the Mayo Medical Labsfree testosterone serum level assay. If using another test with its ownreference range, a person of skill would assess safety serum levellimits in an equivalent way.

High testosterone levels above the reference range have been shown toresult in the harmful effects of testosterone. Females with virilizingovarian tumors provide a good example. Regnier et al., (2002 J. Clin.Endocrinol. Metab. 87(7): 3074) disclose a case study of a woman havinga virilizing ovarian tumor (one that secretes testosterone and resultsin hyperandrogenism in about 80% of cases), with hirsutism that gotprogressively worse over time. Her total testosterone level was between3.9 ng/mL and 7.0 ng/mL, which is well above the reference range forfemales, Table 1. Once the tumor was removed, her testosterone levelreturned to normal, the hirsutism subsided, and the hyperandrogenism didnot recur.

It has also been shown that women with certain conditions, includingbreast cancer, have a total testosterone level higher than the referencerange for women. For example, it has been shown that post-menopausalbreast cancer patients can have a total testosterone level of about 1.55ng/mL, which is above the reference range. Women with testosteronelevels of over 1.55 ng/mL have a four-fold greater chance of developingbreast cancer. (Ho et al., Singapore Med. J., 2009, 50(5):513).

Further, female-to-male (FTM) transsexuals, who are dosed on purposewith testosterone such that their serum levels of total testosteronereach male levels, i.e., >300 ng/dL (>3 ng/mL) have been studied for thesafety of these levels in these genotypic females. Jacobeit (Eur. J.Endocrinol., 2009, 161:795) discloses dosing females to achieve stableserum total testosterone levels within the eugonadal male referencerange of about 620+/−130 ng/dL (6.2+/−1.3 ng/mL) for 36 months. Goorenet al. (J. Sexual Med., 2008, 5:765) teach that the female-to-maletranssexuals receiving doses of testosterone at or above the malereference range develop hirsutism and male-like increased risk forcardiovascular disease and diabetes. Bachmann et al. (Fertil. Steril.,2002, 77(4):660) teach that testosterone and other androgens have manydetrimental side effects, particularly when administered inappropriatelyor at too high of a dose. Specifically, testosterone can cause acne,weight gain, excess hair, increased anger, adverse lipid changes, andabnormal liver function. Franke et al. (Clin. Chem., 1997, 43(7):1262)disclose that over-administration of anabolic steroids can cause manyhealth problems, including weight gain, acne, hirsutism, alteration oflibido, edema, function and structural liver damage. Gooren furtherteaches that the risk of testosterone-induced side-effects, includingcardiovascular disease and hirsutism, are reversed in female-to-maletranssexuals who stop receiving testosterone. Finally, testosterone andother bioactive androgens are Schedule C-III controlled substances underthe Anabolic Steroid Control Act and, as such, can be dangerous toover-administer in view of the dangerous side-effects of cancer, liverdisease, and cardiac disease.

Administration of androgen therapy to males in a safe and effectivemanner. For males, administration of dosages that would bring asubject's testosterone levels above the male reference range alsoresults in similar and well-documented health issues, as discussedabove, although the reference range for males is on the order of about10 times higher than that for females.

Free and/or bioavailable testosterone should be maintained at safe serumlevels for both men and women. All of the above studies show thedifficulty in treating both women and men with testosterone or otherbioactive androgens. It is important to make sure that the dosageadministered to women and men brings the androgen level to the proper,and claimed, range, or the equivalent safe and effective range based onthe detection assay used (see Table 1).

By “safe,” it is meant that serum levels are within the standard errorof the mean SEM of the upper end of the reference range, and there areno unhealthy clinical symptoms of androgen excess. By “effective,” it ismeant that 1) androgen therapy raises baseline serum levels from thelower half of the reference range to significantly higher serum levelsthat are still safe within the reference range, and 2) androgen therapyresults in significant clinical improvement. For example, the androgentherapy can raise the serum androgen levels from the baseline to themiddle or upper portion of the appropriate reference range, and evenslightly higher, so long as the safety profile is maintained. Whiletotal testosterone is a factor when considering the serum levels oftestosterone, it is the free testosterone that is an indicator of thetestosterone that is available for biologic action in vivo. Further,free and bioavailable testosterone generally remain in a constant ratioand are reliable indicators of biologic availability, while SHBG-boundtestosterone, which is not bioavailable, varies in response to changesin the total pool (Felig, P. and L. A. Frohman, “Endocrinology andMetabolism” McGraw Hill, 4th edition, 2001, 647).

Testing serum levels of androgens in men and women. The reference rangesfor women and men differ by a factor of about ten times. Table 1, below,shows the reference ranges for both women and men, and presents datafrom two different reference range detection methods (male referenceranges only shown using one testing method). For example, the DiagnosticSystems Laboratories (DSL) reference range for women is about 0.1 ng/mLto about 1.0 ng/mL. The reference range determined using the MayoMedical Laboratories diagnostic test is from about 0.08 ng/mL to about0.6 mg/mL. Reference ranges are known to differ slightly depending onthe detection kit and method used to measure serum levels. The referencerange for men, as calculated using the Mayo Medical Laboratoriesdiagnostic test is about 2.4 ng/mL to about 9.5 ng/mL. It is importantto remember that, when comparing serum testosterone reference ranges,one must translate the reference range from one test to another. One ofskill in the art would know that diagnostic tests vary in theirreference ranges, according to which, and whether, monoclonal antibody(mAb) was used for detection (earlier detection systems such as DSL usea detection mAb), or whether no mAb was used for detection (morerecently developed detection systems such as Mayo Medical Labs, whichuse tandem mass spectrometry for detection instead). Thus, the upper endof a safe total testosterone serum level range would be at about 1.0ng/dL when using the DSL test, versus about 0.6 ng/dL when using theMayo Medical Labs test. The upper end of a safe free testosterone rangewould be at about 3.3 pg/mL when using the DSL test, versus about 19pg/mL when using the Mayo Medical Labs test. Furthermore, the referencerange is only an approximation of what would be the “normal” range inindividuals, since the reference range would be skewed downward if the“control” population included significant data from subjects with adeficiency. In current times, in which there are abundant stressors inlife, it is highly likely that there will be a significant incidence ofandrogen deficiencies in the population, resulting in androgen referenceranges whose lower end is skewed downward from what is a healthy lowerlimit.

TABLE 1 Testosterone serum reference ranges DSL ref range¹ Mayo refrange¹ Female TT² 0.1-1.0 ng/mL 0.08-0.6 ng/mL (age 40-60 yr) (10-100ng/dL) (8-60 ng/dL) (100-1000 pg/mL) (80-600 pg/mL) Female BioT Notdetermined. 0.008-0.100 ng/mL (age 20-50 yr) (0.8-10 ng/dL) (age >50 yrunkn) (8-100 pg/mL) Female FT² 0.0003-0.0033 ng/mL 0.003-0.019 ng/mL(pre-menopausal) (0.03-0.33 ng/dL) (0.3-1.9 ng/dL) (0.3-3.3 pg/mL) (3-19pg/mL) % of TT that is BioT 10-17% of TT is BioT % of TT that is FT 3-4%of TT is FT % of BioT that is FT 19-38% of BioT is FT Male TT² 2.4-9.5ng/mL (age >18 yr) (240-950 ng/dL) (2,400-9,500 pg/mL) Male BioT0.61-2.13 ng/mL (age 40-49) (61-213 ng/dL) (610-2,130 pg/mL) Male2.0-4.8% of TT is FT % of TT that is FT [~22% of TT is BioT] Male FT0.09-0.3 ng/mL (9-30 ng/dL) (90-300 pg/mL) Abbreviations: TT = totaltestosterone (free testosterone + testosterone weakly bound to albumin +testosterone tightly bound to sex hormone binding globulin SHBG); FT =free testosterone (unbound) BioT = bioavailable (or bioactive)testosterone (free testosterone + testosterone weakly bound to albumin)¹Because reference ranges vary according to the antibody used in thetest, the source of reference ranges used for the values in this tableis indicated: DSL (Diagnostic Systems Laboratories); Mayo (Mayo MedicalLaboratories), a common testing service in hospitals for testing TT, FTand BioT (analysis by tandem mass spec after AmSO₄ precipitation).Claims based on the reference range from an antibody detection test suchas DSL must be converted to the Mayo Medical Labs reference range, whichdoes not rely on antibody detection of testosterone, in order to makecomparisons. The above table can be used for this purpose. ²Maletestosterone levels are generally on the order of 10x femaletestosterone levels; Free testosterone is on the order of 1-5% of totaltestosterone.

For all these reasons, it is desirable for a chronic inflammatory painpatient being treated for androgen deficiency, or clinical symptoms ofandrogen deficiency, to be monitored for their androgen serum levels,including the levels of testosterone, to maintain serum levels safelywithin the SEM of the upper limit of the reference range that isspecific and appropriate for males vs. females. This is true for bothmen and women, even though the testosterone reference range for men andwomen differ by about 10-fold. Conversely, it is desirable for a chronicinflammatory pain patient, or a patient being treated for clinicalsymptoms of distress, as shown in paragraphs [0011], [0029] and [0041]above, who is being treated for androgen deficiency, or clinicalsymptoms of androgen deficiency, to raise their serum levelssignificantly from their baseline level towards/into the upper end ofthe reference range to achieve clinical efficacy.

For the purpose of this instant invention, chronic pain, as is normallyconsidered within the clinical arena, is inflammatory pain and isdistinct from the non-inflammatory tender point muscle pain offibromyalgia. The chronic inflammatory pain group of patients (havingpain for at least three months, or with unresolvable pain) can bescreened for androgen serum levels. Patients to be treated will presentan androgen serum level in the lower half of the appropriate referencerange.

When considering the low pain threshold group of patients, this includesthose patients with substantial stress that cannot be resolved throughcoping or adaptation (i.e., stress becomes distress). These patientswould be likely to have clinical signs or conditions of stress, asdiscussed in paragraphs [0011], [0029] and [0041] above. Or they couldhave clinical signs, for example a lack of feeling of well-being or alow libido (lacking the ability to enjoy life), that suggest a high riskof more overt symptoms of clinical distress. The serum androgen levelscan be checked and if found to be in the lower half of the appropriatereference range, these patients can also be checked for a low painthreshold using a dolorimeter (or other appropriate measurement systemor metric). A low pain threshold correlated with serum androgen levelsin the lower half of the appropriate reference range would constitutethe group of patients to be treated.

Generally, patients as described above can be stratified by lower halfof androgen (or testosterone) reference range and low threshold of painversus those patients having serum levels in the upper half of thereference range and a normal threshold of pain. The first group arecandidates for treatment according to the methods of the invention.Those in the second group should not be treated by these methods, orthey can be used in a placebo arm.

Drawbacks to current therapeutics such as anti-depressants for treatingchronic inflammatory pain in the clinic. Doctors have begun to employanti-depressants, as well as cognitive behavioral therapy, for thetreatment of pain. For example, serotonin-norepinephrine reuptakeinhibitors (SNRIs), such as duloxetine, and selective serotonin reuptakeinhibitors (SSRIs), such as fluoxetine and sertraline, and the tricyclicclass of antidepressants can be useful for treating pain. Unfortunately,patients undergoing therapy with these pharmaceuticals can suffer fromeither a lack of efficacy and/or unintended side effects that arefrequently worse than the benefits, such as sexual side effects (e.g.,arousal disorder and difficulty achieving orgasm), as well as an FDAmandated black box warning for increased risk of suicidality. Othercommon side effects of these drugs are nausea, ejaculation failure,insomnia, dizziness, tremor, and decreased libido, as well as exhaustionof testosterone concentrations due to anti-depressant drug treatment.

Numerous clinical states relate to decreased androgen levels and thus toa high risk for chronic pain and chronic stressor states. The treatmentdisclosed herein can alleviate any of these conditions and furtheralleviate problems caused by other therapeutics, wherein the conditionsand therapeutically-induced problems relate to or cause decreased or lowtestosterone. There are several chronic conditions that affect T levelsdirectly. Some chronic medical conditions and illnesses will affectand/or decrease testosterone levels directly. For example, orchidectomyor bilateral oophorectomy (surgical removal of testes or both ovaries)can decrease testosterone levels by as much as 50%. Low testosteronelevels are also associated with hypothalamic, pituitary, and/or adrenalinsufficiency. Hypopituitarisms of any cause, including, but not limitedto, Sheehan's syndrome, and adrenal disease, including Addison'sdisease, can cause low testosterone levels. Finally, chronic illnessesincluding, but not limited to, anorexia nervosa, clinical depression,advanced cancer, and burn trauma are also causative of low testosteroneconcentrations. Of note, advancing age is also associated with reducedlevels of testosterone and its precursors, DHEA and androstenedione.This likely is caused by natural aging of the ovaries/testes and adrenalglands.

Drugs given to subjects systemically can also cause decreasedtestosterone levels. Examples of pharmaceutical agents that can causedecreased testosterone levels include, but are not limited to, systemicglucocorticoids or oral estrogens. The decreased levels of testosteroneare associated with the suppression of adrenocorticotropic hormonelevels with glucocorticoid use and luteinizing hormone levels with oralestrogen therapy. Oral estrogen users have significantly lower levels offree testosterone, due to increased levels of sex hormone-bindingglobulin (SHBG). Both hyperthyroidism and excessive thyroid medicationalso increase SHBG levels, which lead to lower levels of freetestosterone. In these cases, both the conditions and the treatments cancause lower levels of testosterone.

Other pharmacological agents that can lower testosterone directlyinclude, but are not limited to, trazodone, imipramine, musclerelaxants, analgesics (e.g., non-steroidal anti-inflammatory drugs(NSAIDS), COX-2 inhibitors (e.g., celecoxib, tramadol), sleepmedications (e.g., zolpidem, alprazonam), barbiturates, sedatives,clonidine, methyldopa, spironolactone (which has antiandrogenicproperties), and selective androgen receptor modulators (SARMs).Further, drugs that otherwise ablate selective portions of pathwaysinvolved in effecting androgen responses, also affect testosterone serumlevels. These drugs include, but are not limited to, competitiveinhibitors of 5-alpha reductase (the enzyme that converts testosteroneto dihydrotestosterone) (e.g., finasteride, dutasteride),gonadotropin-releasing hormone (GnRH) agonists (e.g., goserelin, whichdeprives tumors of testosterone, leuprolide, buserelin, naferelin,deslorelin), GnRH antagonists (e.g., cetrorelix, abarelix, ganirelix,degarelix), anti-androgens that bind to androgen receptors as anantagonist (e.g., bicalutamide, flutamide, both used to treat prostatecancer), corticosteroids (e.g., cortisol, aldosterone, cortisone,prednisone, dexamethasone, triamcinolone, budesonide), and ketoconazole.

In addition, use of various recreational drugs (e.g., alcohol,marijuana, cocaine, heroin, methadone) can also cause decreases intestosterone and sexual function.

Chronic medical conditions that are treated, for example withanti-depressants, can also be associated with decreased testosteronelevels. One set of medical conditions can include, but is not limitedto, medical conditions being treated with certain medications,especially antidepressants. Specific indications might be decreasedsexual function in both men and women. Such indications includepsychosocial issues and psychological disorders (including, but notlimited to, depression and anxiety), physiological/medical conditions(including, but not limited to menopause, age-related sexual drivedecline, and fatigue). Another set of medical conditions that might betreated with antidepressants includes all forms of chronic illnesses(including, but not limited to cardiovascular disease, diabetesmellitus, arthritis, renal failure and cancer. Gynecological and/orbreast cancer can be particularly causative of such problems).

Patients exhibiting the aforementioned conditions, which also have acomponent relating to a low sex drive and/or low testosterone levels canbe treated by a variety of pharmacological agents. For example,depression and anxiety can be treated with any one of a number ofagents, including but not limited to, tricyclic antidepressants (e.g.,amitriptyline, clomipramine, butriptyline, doxepin), selective serotoninreuptake inhibitors (SSRIs) (e.g., fluoxetine, sertraline, citalopram,paroxetine), serotonin-norepinephrine reuptake inhibitors (SNRIs) (e.g.,duloxetine, venlafaxine, desvenlafaxine), anxiolytics and antipsychotics(e.g., antidepressants, antihistamines, benzodiazepines, azaspirones),and beta blockers (e.g., carvediol, acebutolol, metoprolol, atenolol,timolol, labetolol). Both the conditions treated and the agents used totreat these conditions can decrease testosterone levels, exacerbatingthe androgen deficiency, or symptoms thereof.

The instant invention can be used as a primary therapy and concurrentlywith the aforementioned pharmacological agents, and can counteract thedecreased sexual function and low levels of testosterone resulting fromthe conditions being treated, as well as the pharmacological agentsbeing used to treat those conditions.

Although caused at least in part by the stress (“distress,” usingSelye's terms) of disease and illness, the detailed precipitatingmechanism of testosterone decrease is not well defined. However, thedescriptions presented here go a significant way toward providing acoherent overview that is strongly supported by the data pulled togetherherein.

As stated above, antidepressants can also be taken as an adjunctivetherapy in conjunction with primary androgen therapy. Here, it is likelythat the benefits of androgens can work in concert with the benefits ofthe SNRIs, SSRIs or tricyclic antidepressants. Therefore, the inventionfurther relates to 1) the treatment of pain comprising administering anandrogen alone or in combination with an antidepressant, or 2) thetreatment of depression as an unresolvable state of distress or combinedwith a lack of feeling of well-being, comprising administering anandrogen alone or in combination with an antidepressant, and 3) whenthese patients have serum levels of androgen in the lower half of thereference range. The androgen can be those previously described. Theantidepressant can be selected from SSRIs or SNRIs including duloxetine,fluoxetine, sertraline, and a tricyclic antidepressant. The dosage ofthe antidepressant compounds can be the usual range of administrationfor these compounds. Treatment can be the androgen either alone or incombination with antidepressant compounds.

The Circle Hypothesis provides a mechanistic basis and the overallbiologic context or paradigm for a rational treatment of clinicalsymptoms of androgen deficiency. The underlying circle hypothesis, asdescribed above, applies to both the chronic pain, and/or the abnormallylow pain threshold patient populations comprised of patients in a stateof distress or lacking a feeling of well-being. Using the informationgleaned from the testing protocols, one can appropriately select thepatients for androgen therapy.

Methods for evaluating and treating subjects. The invention, therefore,also relates to a method of determining if a subject should be treatedwith androgen therapy. Such a method can comprise testing a subject forandrogen serum levels; testing the subject for the subject's painthreshold, wherein if the subject has low androgen serum levels and alow threshold of pain or clinical evidence or symptoms of androgendeficiency as defined elsewhere, an androgen is administered to thesubject.

In one embodiment of the invention, the bioactive androgen may be atestosterone ester such as, but not limited to, testosterone enanthateor testosterone cypionate. In another embodiment of the invention, thebioactive androgen is testosterone. As described above, this isapplicable to both the method of treating chronic pain in a subject andthe method of increasing the pain threshold in a subject.

Female dose. In one embodiment of the invention, and for both the methodof treating chronic pain in a female human subject and the method ofincreasing the pain threshold in a female subject, the androgen can beadministered in a unit dose of about 0.1 mg to about 12.8 mg of theandrogen. In one embodiment, the androgen can be formulated as atransdermal preparation in a pharmaceutically acceptable carrierformulated for daily topical administration as a gel and wherein the gelis formulated to deliver steady state total androgen serum levelswithout raising free androgen serum levels or twenty-four hour freeandrogen AUC above the levels required for therapeutic efficacy andsafety. Preferably, the daily unit dose of the androgen is from about1.0 mg to about 12.8 mg. More preferably, the daily unit dose of theandrogen is from about 2.5 mg to about 10.0 mg. Even more preferably,the daily unit dose of the androgen is from about 3.2 mg to about 9.6mg. Most preferably, the daily unit dose of the androgen is from about6.0 mg to about 8.0 mg. The daily unit dose of the androgen can be about6.5 mg or about 7.5 mg.

In another embodiment, the dosing range can be incremental. For example,the dose to be administered to a female subject can be about 2.5 mg; 5.0mg; 7.5 mg; or 10.0 mg. In order to determine the most appropriatedosage for a particular subject, a physician may start the patient on alow dose, and titrate the dose upwards until a dose that is botheffective and safe is reached. In yet another embodiment, theincremental dosage rate can start at 3.2 mg, and rise progressively to6.4 mg, 9.6 mg, and 12.8 mg, using a 0.8% gel formulation. For example,and in the case of a transdermal preparation, patients can be startedwith 2 packets of 0.8% testosterone or placebo gel per day for the firstfour weeks. Each packet can contain 400 mg of 0.8% testosterone gel (3.2mg testosterone, to deliver 10% or 320 pg bioavailable testosterone) or400 mg placebo gel in it. After four weeks, any patient who tests >3.3pg/mL for serum free testosterone (testosterone serum levels above theDSL reference range), can decrease the dose by one gel packet/day. Anypatient who tests ≦1.9 pg/mL for serum free testosterone (within orbelow the lower half of the DSL testosterone reference range) canincrease the dose by one gel packet/day until the serum level is raisedto between about the mid-range and the upper end of the reference range+/−SEM. It is the level of free testosterone and/or bioavailabletestosterone, rather than total testosterone, that is important tomaintain within the reference range +/−SEM, since it is freetestosterone or bioavailable testosterone that correlates tightly withsafety.

In one embodiment of the invention, the daily unit dose can be deliveredvia a transdermal gel having about 0.1% to about 10.0% of the androgen.Preferably, the transdermal gel can have about 0.5% to about 5.0% of theandrogen. More preferably, the transdermal gel can have about 0.5% toabout 2.5% of the androgen. Most preferably, the transdermal gel canhave about 0.8-1.0% of the androgen.

The daily unit dose of the androgen can be from about 4.0 mg to about10.0 mg, or from about 6.0 mg to about 8.0 mg. At 10% bioavailabilityfor the androgen in the gel that is actually delivered to the blood, thedaily unit dose-to-be-delivered of the androgen can be from about 0.4 mgto about 1.0 mg, or from about 0.6 mg to about 0.8 mg androgen.

The formulation of the invention will preferably be used at a unit doseof 800 mg gel of 0.8% testosterone (6.4 mg testosterone), and then,depending on serum levels at 4 weeks, adjusting down to 400 mg gel of0.8% testosterone (3.2 mg testosterone), or adjusting up to 1200 mg gelof 0.8% testosterone (9.6 mg testosterone), to maintain the unit dose toachieve safe and effective serum levels.

Alternatively, testosterone can be administered to females in a varietyof different ways, including, but not limited to injection, oraladministration, buccal administration, implanted pellets, orsuppositories. If an alternate method of administration is chosen forfemales, the regimen of administration may also be varied, as describedabove in paragraph [0087].

Androgen serum level targets for females. In another embodiment of theinvention, and for both the method of treating chronic pain in a subjectand the method of increasing the pain threshold in a female humansubject, the daily unit dose of the androgen may be selected to maintainsteady state total androgen serum levels within a range of between about0.7 ng/mL and about 1.6 ng/mL, and preferably between about 0.9 ng/mLand about 1.4 ng/mL for at least 24 hours after administration withoutraising free androgen serum levels or twenty-four hour free androgen AUCabove the levels required for therapeutic efficacy and safety, asdefined elsewhere herein. Further, the free androgen serum levels andtwenty-four hour free androgen AUC should not be raised above levelsrequired for therapeutic efficacy and safety. Specifically, the freeandrogen serum levels can be raised to between about 1.00 pg/mL andabout 3.3 pg/mL+/−2 SEM. (About 3.3 pg/mL using the DSL test isequivalent to about 19 pg/mL using the Mayo Medical Labs massspectrophotometry method of measuring free testosterone, Table 1. Theupper end of the reference range is determined by which method ofmeasuring free testosterone is used). The twenty-four hour free androgenAUC levels can be raised to between about 35.18 pg-h/mL and about 72.60pg-h/mL; more preferably the free androgen serum levels can be raised tobetween about 2.00 pg/mL and about 3.3 pg/mL and the twenty-four hourfree androgen AUC levels can be raised to between about 40 pg-h/mL andabout 65 pg-h/mL. For a postmenopausal woman with clinical symptoms ofandrogen deficiency, the full reference range of the premenopausal womancan be used to determine the optimal desired serum testosterone level.

Male dose. In yet another embodiment of the invention, and for both themethod of treating chronic pain in a male human subject and the methodof increasing the pain threshold in a male human subject the androgen isadministered in a unit dose of about 35 mg to about 100 mg of theandrogen. In one embodiment, the androgen can be formulated as atransdermal preparation in a pharmaceutically acceptable carrierformulated for daily topical administration as a gel. Further, the gelis formulated to deliver steady state total androgen serum levelswithout raising free androgen serum levels or twenty-four hour freeandrogen AUC above the levels required for both therapeutic efficacy andsafety.

In one embodiment of the invention, the daily unit dose of the androgenfor a male can be from about 50 mg to about 90 mg/day or from about 65mg to about 85 mg. Alternatively, the daily unit dose of the androgencan be about 75 mg or about 80 mg. In one embodiment, as exemplifiedhere, the unit dose above can be administered as a once-a-day daily unitdose of a transdermal gel, whereby steady state serum androgen levelsare reached within 24 hours. Alternative formulations and dosing can beused (as discussed above in paragraph [0087], although the preferredembodiment is a formulation that holds to the safe delivery of“not-too-much-too-fast” testosterone, i.e., without unsafe spiking whileraising blood levels above baseline to achieve clinical efficacy, and adelivery rate that achieves steady state within days of initiatingtherapy. For other routes of administration, the dosage can be easilyvaried by one of ordinary skill in the art. Ultimately, the safe andeffective reduction of pain and the concomitant desired serum levels ofthe androgen can be obtained using varied routes of administration andvaried dosage levels, which can be determined on a case-by-case basis.

In another embodiment, the dosing range can be incremental. For example,the dose to be administered to a male subject can be about 50 mg; 75 mg;80 mg; or 90.0 mg. In order to determine the most appropriate dosage fora particular subject, a physician may start the patient on a low dose,and titrate the dose upwards until a dose that is both effective andsafe is reached. In yet another embodiment, the incremental dosage ratecan start at 50 mg, and rise progressively to 70 mg, 80 mg, and 90 mg.In the case of a transdermal preparation, patients can be started withan appropriate number packets of a testosterone gel formulated for malesby one of ordinary skill in the art or placebo gel per day for the firstfour weeks. Each packet can contain the appropriate amount of atestosterone gel or the corresponding placebo gel. After four weeks, anypatient who tests above the appropriate male reference range for serumfree testosterone, can decrease the dose over time until the appropriatereference range is reached and maintained. Any patient who tests at orbelow the lower half of the male reference range for serum free canincrease the dose over time until the serum level is raised to betweenabout the mid-range and the upper end of the reference range +/−SEM. Asabove, it is the level of free testosterone and/or bioavailabletestosterone, rather than total testosterone, that is important tomaintain within the reference range +/−SEM, since it is freetestosterone or bioavailable testosterone that correlates tightly withsafety.

In one embodiment of the invention, the daily unit dose can be deliveredvia a transdermal gel having about 0.1% to about 10.0% of the androgen.Preferably, the transdermal gel can have about 0.5% to about 5.0% of theandrogen. More preferably, the transdermal gel can have about 0.5% toabout 2.5% of the androgen. Most preferably, the transdermal gel canhave about 0.8-1.0% of the androgen.

Alternatively, testosterone can be administered to males in a variety ofdifferent ways, including, but not limited to injection, oraladministration, buccal administration, implanted pellets, orsuppositories. If an alternate method of administration is chosen formales, the regimen of administration may also be varied as describedabove in paragraph [0087].

Androgen serum level targets for males. The daily unit dose of theandrogen for a male can be selected to maintain steady state totalandrogen serum levels within a range of between about 2.4 ng/mL to about9.5 ng/mL for at least 24 hours after administration. In addition, thefree androgen serum levels and twenty-four hour free androgen AUC shouldnot be raised above the levels required for therapeutic efficacy andsafety, as defined elsewhere herein. Specifically, the free androgenserum levels can be raised to between about 90 pg/mL and about 300 pg/mLand the twenty-four hour free androgen AUC levels can be raised tobetween about 350 pg-h/mL and about 800 pg-h/mL; more preferably thefree androgen serum levels can be raised to between about 150 pg/mL andabout 300 pg/mL and the twenty-four hour free androgen AUC levels can beraised to between about 400 pg-h/mL and about 700 pg-h/mL. As above,these preferred ranges can be adjusted for the Mayo Medical Labsreference ranges or any other reference laboratory.

In another embodiment of the invention, the unit dose for male subjectscan be selected to maintain steady state total androgen serum levelswithin a range of between about 4.0 ng/mL and about 9.5 ng/mL,preferably between about 6.0 ng/mL and about 9.5 ng/mL, for at least 24hours after administration without raising free androgen serum levels ortwenty-four hour free androgen AUC above the levels required fortherapeutic efficacy and safety, as defined elsewhere herein.

Transdermal gel formulations for an androgen and at least onepharmaceutically acceptable carrier. Formulation of transdermal gels arestandard and well known in the art, and can contain a wide variety ofcomponents, including penetration enhancers. Penetration enhancers havedifferent strengths and can be optimized to obtain the desiredtransdermal delivery effect. For example, penetration enhancers such asoleic acid and sodium hydroxide are stronger and allow for more andfaster delivery of a transdermally-delivered drug and are frequentlyused in androgen compositions approved for male use. These formulationsare based on the idea that inclusion of such male-specific penetrationenhancers may help achieve absorption of the relatively high amounts oftestosterone that males require. If too potent a penetration enhancer isused, the blood stream can be flooded with drug too fast, resulting in“too-much-too-fast” delivery profiles. In many male formulations, it isapparent that these potent penetration enhancers are being used, becausethe compositions containing such penetration enhancer componentsfrequently results in a spike in androgen serum levels. Such a spike,usually in the first two hours after administration, can preventsustained and effective delivery of androgens in both males and females.Further, depot preparations that are sometimes used for males, delivertoo much androgen, too quickly. Finally, male transdermal formulationscarry a black box warning regarding transmission of the gel from thepatient to others in contact with the patients, while depotintramuscular injections risk too-high levels of testosterone initially,with too-low levels at the tail end of the delivery period of time.

Less potent penetration enhancers can be used for a more even drugdelivery profile. In addition, transdermal formulations using lesspotent or no penetration enhancers can be absorbed into the skin at amore even rate without unsafe spiking. Such penetration enhancers areemployed for the instant invention and can be used such that unsafespiking is avoided while robust and safe delivery is achieved, even inmales. During transdermal delivery, a portion of the androgen goesdirectly into the blood stream and a portion of the androgen is absorbedby fatty tissues. Since testosterone and other androgen compounds arehydrophobic, they are retained in the fatty tissue and are released intothe bloodstream evenly and over a sustained period of time due to theinherent hydrophobic properties of testosterone residing in the inherenthydrophobic environment of the fatty tissues. Steady state androgenblood levels are reached generally within 24 hours, if not sooner.

In addition, the invention relates to the safe and effectiveadministration of a transdermal composition comprising an androgen totreat chronic pain, to increase the pain threshold of a subject, and toincrease production of endogenous opioid peptides in a subject. Thecomposition can also consist essentially of an androgen. The inventionfurther relates to administration of a transdermal composition thatsignificantly and uniquely raises serum levels of the androgen (e.g.,testosterone) to a level approximating the upper portion of theappropriate reference range. The invention also relates toadministration of an androgen composition as the primary therapy topatients that are either undergoing exogenous opioid treatment as anadjunctive therapy, as well as administration of the androgencomposition to patients who are not undergoing concurrent exogenousopioid therapy. Further, other compounds, such as, but not limited to,antidepressants can also be administered as an adjunctive therapy to theprimary androgen therapy.

One of skill in the art would be able to derive a formulationappropriate for males or females, and appropriate to attain the requiredserum androgen levels that are both safe and efficacious. Pharmaceuticalhandbooks provide a wealth of information to the transdermal compositionformulator, and assist the formulator in determining the appropriatecomposition to obtain the desired drug delivery profile. Texts such asAnsel's Pharmaceutical Dosage Forms and Drug Delivery Systems (eds.Allen, Jr., et al., Lippincott Williams & Wilkins, Philadelphia, 8^(th)Edition, 2005 and Remington: The Science and Practice of Pharmacy (ed.Alfonso R. Gennaro, Lippincott Williams & Wilkins, Philadelphia, 20^(th)Edition, 2000) contain chapters relating to transdermal formulations,and components that might be used therefor. Using such well-knowninformation and techniques, one of ordinary skill in the art would beable to formulate a transdermal androgen composition and to adjust thecomponent type and concentration, so that the resulting serum androgenlevels are both safe and efficacious, are within the appropriatereference range, and achieve a steady state within twenty-four hourswithout a potentially dangerous spike in androgen serum levels. Theformulation chosen would improve clinical symptoms of androgendeficiency, pain, and/or distress without causing either unsafe clinicalsymptoms of androgen excess or an ineffective androgen administration.

The transdermal gel formulation has advantages over current methods, aswell as transdermal patch methods, that include 1) steady state withinabout 24 hours, 2) even delivery over each daily 24 hour period withonce-a-day dosing and without over-shooting the upper limit of thereference range, 3) avoidance of delivering too-much-drug-too-fast andthe resultant unsafe serum spiking profile over each 24 hour period oftime, 4) avoidance of first pass metabolism effect, 5) avoidance of skinirritation seen with some other gels and with the patch, 6) all of whichoptimize safety and efficacy with respect to raising serum testosteronelevels significantly above baseline levels, and with respect toachieving significant clinical efficacy in reducing inflammatory pain orincreasing the pain threshold or increasing endogenous opioid peptideswithout evidence of androgen excess or harmful clinical side effects.

Routes of administration. As will be obvious to those of skill in theart upon this disclosure, other pharmaceutically acceptable androgentherapies can be used, as long as the desired serum androgen profilesare obtained. Effective amounts and routes by which the androgen orcombination of androgens can be administered in a safe and effectivemanner according to the present invention can also be used, and aredescribed in paragraph [0087] above.

The androgen can be administered transdermally, orally (as an immediaterelease tablet or capsule, an orally disintegrating tablet or capsule,and enterically coated tablet or capsule, and a delayed release tabletor capsule, or a form of an androgen as a prodrug), by injection(intramuscular, intraperitoneal, intravenous, or subcutaneous); bybuccal administration, via an implanted pellet, a dragee or asuppository. One of skill in the art would be able to adjust the dosagesdelivered by these methods, so that the delivery of the androgencomposition to the bloodstream results in the desired safe andefficacious androgen serum levels.

The bioactive androgen can be formulated with a pharmaceuticallyacceptable carrier. Such carriers include, but are not limited to,saline, buffered saline, dextrose, water, glycerol, ethanol, andcombinations thereof. The term specifically excludes cell culturemedium. For drugs administered orally, pharmaceutically acceptablecarriers include, but are not limited to pharmaceutically acceptableexcipients such as inert diluents, disintegrating agents, bindingagents, lubricating agents, sweetening agents, flavoring agents,coloring agents and preservatives. Suitable inert diluents includesodium and calcium carbonate, sodium and calcium phosphate, and lactose,while corn starch and alginic acid are suitable disintegrating agents.Binding agents may include starch and gelatin, while the lubricatingagent, if present, will generally be magnesium stearate, stearic acid ortalc. If desired, the tablets may be coated with a material such asglyceryl monostearate or glyceryl distearate, to delay absorption in thegastrointestinal tract.

For transdermal administration, the formulation can include, but is notlimited to, the androgen, a penetration enhancer or excipient, anemulsifier, a gelling agent; a lubricant, a thickening agent, a solventor co-solvent, emollient, humectant, protein stabilizer, moisturizer,crystallization inhibitor, neutralizing agent, a buffer, an alcohol, andwater. Variations of the formulation and routes of administration willbe evident to one of skill in the art such that, upon administration ofthe bioactive androgen, both safe and effective serum levels of androgenare obtained.

For intramuscular, intraperitoneal, subcutaneous and intravenous use,the androgen compositions of the invention will generally be provided insterile aqueous solutions or suspensions, buffered to an appropriate pHand isotonicity. Suitable aqueous vehicles include Ringer's solution andisotonic sodium chloride. Aqueous suspensions according to the inventionmay include suspending agents such as cellulose derivatives, sodiumalginate, polyvinyl-pyrrolidone and gum tragacanth, and a wetting agentsuch as lecithin. Suitable preservatives for aqueous suspensions includeethyl and n-propyl p-hydroxybenzoate.

In addition, androgen therapy provides a useful means for alleviatingunresolvable pain, both acute and chronic. Chronic pain is defined byneurologists as pain lasting three months or longer. Chronic pain isparticularly debilitating, and can be diffuse or localized. Acute pain,or pain lasting less than three months, can likely also be treated withandrogen therapy, as long as the acute pain is associated with aconcurrent androgen deficiency or symptoms of androgen deficiency. Anacute pain appropriate for treatment would likely be related to anunresolvable stress or state of distress and/or an abnormally lowthreshold of pain.

In a preferred embodiment, the androgen administered as the primary paintherapy is testosterone, an active metabolite of testosterone such asdihydrotestosterone or androstenedione or a testosterone derivative suchas methyltestosterone, testosterone enanthate or testosterone cypionate.Examples of available pharmacologic preparations of androgens believedto be useful in this invention include, but are not limited to danazol,fluoxymesterone, oxandrolone, methyltestosterone, nandrolone decanoate,nandrolone phenpropionate, oxymethalone, stanozolol, methandrostenolone,testolactone, pregnenolone and dehydroepiandrosterone (DHEA).

The “Circle Hypothesis.” As described in detail above, FIGS. 3A-3B showthe proposed metabolic pathway for testosterone in relation tonociception. Other bioactive androgens may also be employed in thetreatment of chronic pain. FIGS. 3A-3B show the hypothesized metabolicpathway in normal subjects and subjects with chronic pain. FIG. 3A showsthat, in normal individuals, a painful/stressful stimulus upregulatesSubstance P in nociceptive relay neurons and concurrently serotoninlevels drop. This is consistent with a loss of feeling of well-being.Substance P, in turn has been found to stimulate aromatase, which allowsfor the conversion of testosterone to estradiol within the centralnervous system, with subsequent upregulation of opiates and/orenkephalinergics and other pain dampening mediators, with consequentdampening of pain and Substance P. In FIG. 3B, subjects with deficientlevels of testosterone are predicted to have a frustrated cycle in whicharomatase fails to convert testosterone to estradiol due to thedeficiency of androgen, leading to insufficient induction of opiatepeptides and/or other mediators to dampen Substance P and nociceptivesignals, resulting in abnormal chronic, diffuse, widespread pain, aswell as wind-up exacerbation of pain and clinical states of distress.Essentially, when the body is subjected to a painful and/or stressfulstimulus, testosterone metabolism is stepped up as a mechanism to copewith and overcome pain. When androgens, such as testosterone, aredepleted, which they are under conditions of stress (Opstad, J., 2002,74: 99-204), then the body's pain-fighting mechanisms break down.Androgen therapy can thus break this frustrated cycle, and alleviateboth acute and chronic pain that is exacerbated with androgendeficiency, or symptoms of androgen deficiency.

Example 1

Proof of concept for efficacy and safety of androgen therapy for tenderpoint pain. The fact that it is testosterone rather than estrogen thatis the important therapeutic to administer is suggested by thesignificant decrease in serum-derived free testosterone concentrations(unbound testosterone) that has been documented for premenopausal femalefibromyalgia patents relative to healthy volunteers. (Dessein P H etal., 1999 Pain 83: 313). The pharmacokinetics, clinical efficacy andsafety of transdermal delivery of androgen hormone for treatment offibromyalgia in women was previously demonstrated in a phase 1-2clinical trial (U.S. Pat. No. 7,799,769 B2). The transdermaltestosterone gel used for that study was shown to be both safe andclinically effective. The distinct difference between fibromyalgia andthe chronic inflammatory pain states in the present invention isevidenced by 1) the different and non-overlapping types of clinicianswho normally treat the two types of pain, 2) distinct differences in DSMdiagnostic criteria, 3) distinct differences in the genesis of chronicpain and their etiologies (fibromyalgia muscle tender point pain isknown to be uniquely non-inflammatory), and 4) distinct differences insymptoms and clinical treatments. For all the reasons mentioned above,an expert knowledgeable in the treatment of chronic inflammatory painwould not think to utilize androgen gel therapy for a chronicinflammatory pain state. This is underscored by the fact that androgentherapy is not currently used to treat any chronic inflammatory painstates in the clinic. Thus, the present invention offers a unique anddistinct indication and treatment method. However, the afore-mentionedstudy shows that a transdermal androgen gel formulation can be used tosignificantly raise the serum levels of testosterone in women withfibromyalgia safely and in a clinically effective way.

In the study cited in U.S. Pat. No. 7,799,769 B2, testosterone wasformulated as a gel and used to treat women with low androgen levels.Pharmacokinetic analysis of the serum testosterone concentration datafrom these testosterone gel treated patients revealed that mean serumtotal and free testosterone concentrations were significantly increasedfrom levels in the lower half of the reference range to levels in theupper portion of the reference range in response to therapy. Mean serumconcentrations were increased quickly, within a few hours, with steadystate being reached within 24 hours, with no unsafe spiking, andmaintained to the end of the 28 day time course. Thus, in response totherapy, these increased serum levels equilibrated at steady state andremained at safe levels. Significant clinical efficacy in the treatmentof fibromyalgia patients was demonstrated with respect to decreasedmuscle tender point pain, as well as ablatement of otherfibromyalgia-unique symptoms. Symptoms that were not specific forfibromyalgia were not significantly changed. The sum of the tender pointtests showed a statistical significance with a p value of 0.012 on day28 vs. day 1. Tender point examinations (a test designed specifically tomeasure fibromyalgia-related symptoms) were administered by a qualifiedrheumatologist experienced in and knowledgeable about the criteriaspecified by the American College of Rheumatology. It is noted thatthese patients saw a rheumatologist, rather than a neurologist. Achronic inflammatory pain patient would see a neurologist who hasdifferent training and skill sets to treat this condition.

The delivery of drug in a safe manner in women was achieved by takinginto account the unique sex steroid hormone physiology of women comparedto men. This formulation uniquely provides the correct pharmacokineticprofile women need, raising their total and free testosterone serumlevels to clinically effective levels within hours, while notover-shooting safe serum levels—as defined, in part, by maintaining meanfree testosterone levels within the upper end of the reference range forwomen, as well as the avoidance of any clinical symptoms of androgenexcess. The strong clinical safety profile included the followingcomponents: 1) normal cardiac function, liver function and kidneyfunction after blood panel assessment, 2) clinical assessment showingmaintenance of good overall general health in the study patients, 3) noadverse events attributable to the treatment, and 4) no clinicalevidence of androgen excess such as hirsutism or unhealthy change incardiovascular parameters. Others have shown that androgen excess inwomen, for example female-to-male transgender patients, readily havethese symptoms of androgen excess.

Male formulations, by necessity, require excipients or skin permeationenhancers to quickly and effectively deliver the large bolus of androgenthat men require for effective clinical treatment. When applied towomen, male gel formulations can deliver a bolus of too muchtestosterone too fast, overwhelming biologic pathways that are uniquelydifferent in female androgen physiology. Such gels can inherently haveproperties such that they may either be used at too low a volume of gelin order to maintain safety and avoid overshooting the female referencerange, or they can be used at an unsafe and too high a volume in orderto maintain clinically effective delivery of drug after the early peakof high serum levels, i.e., during the second half of the 24 hourdelivery profile when levels are too low to maintain efficacy over theentire 24 hour period.

In summary, Example 1 offers proof of concept that women with decreasedandrogen levels can receive a transdermal testosterone gel formulation,with a delivery profile designed uniquely appropriate for women thatavoids the inherent pitfalls associated with the usage of a maletestosterone gel formulation in women. These results, from thestandpoints of 1) pharmacokinetic efficacy (the serum levels weresignificantly raised), and 2) safety (the serum levels were maintainedat safe free testosterone reference range levels and there were noclinical or blood panel symptoms of androgen excess) support thefunctional properties of the tested testosterone transdermal gelformulation to treat individuals with chronic pain. This Exampleillustrates significant improvement in fibromyalgia-relatednon-inflammatory muscle tender point pain in patients.

PROPHETIC EXAMPLES Planned Prophetic Studies

Clinical studies in two different types of patients will be conducted inthe future to confirm the effectiveness of androgen therapy to 1)alleviate pain and 2) increase the threshold of pain. Specifically,patients will be examined for reductions in chronic pain and modulationof pain threshold following an improvement in serum androgen levels. Theinitial drug delivery vehicle will be a gel formulation using atransdermal delivery system androgen that will result in safe andeffective serum levels. After initial treatment, serum levels will bemonitored in order to maintain levels within the appropriate referencerange and avoid adverse effects. A dose resulting in an androgen levelabove the reference range will be reduced such that a safe and effectivedose is maintained. Females will be the first to be studied; males willthen be studied with a similar approach. The most likely formulationstudied initially will be a 1% or a 0.8% testosterone gel to beadministered as a daily unit dose for females. A male formulation todeliver about ten times the amount of active androgen will be testedsubsequently. All studies can include an arm wherein the subjects arenot undergoing concurrent exogenous opioid therapy.

Prophetic Example 1 Population Study to Screen Subgroups of PainPatients for Serum Testosterone Levels.

Patients with various types of chronic or unresolved pain will first bescreened for testosterone levels in the lower half of the appropriatereference range. Pain patients will be categorized by gender and mayinclude, but are not limited to, cancer patients, post-surgicalpatients, accident victims, combat veterans, patients with neuropathy,hyperalgesia, allodynia, depression, and rheumatologic/autoimmunedisorders. These subsets of patients will also be stratified byassessment of their clinical symptoms of androgen deficiency. Blood willbe taken by venipuncture at the start of treatment and again at each ofseveral specific time points in the study for each of the patientgroups. Androgen levels will be determined by a laboratory expert inhandling clinical trial samples and testing hormone levels in humans.One skilled in testing for serum levels of the sex steroid hormones,including testosterone, will know standard practices for blood draws.Patient groups will be separated into female and male subsets. Otherdiagnostic or therapeutic tests will be used as appropriate. A VisualAnalog Scale (VAS) pain perceived assessment test is an example of sucha test. Blood will be drawn at a common time of day, preferably the peaktime for androgens, at 8 AM, after fasting since midnight. Other testingmight include total serum hormone levels, free serum hormone levels,serum binding globulins, serum estradiol levels, evaluations of cardiachealth, kidney function and liver function, physical function,psychological function, and metrics for restorative sleep. The studyphysicians will also complete a Physician's Form. Results will bestratified by androgen serum levels and symptoms of androgen deficiency.

Prophetic Example 2

Open Label Testosterone Therapy Study of Patients with Pain.

Proof of Concept Study in pain to test efficacy of androgen therapy inpatients with pain. One or two of the groups evaluated above will bechosen as a test population for an efficacy study preliminary to largerclinical trials. The initial target will be the group, or groups, ofpatients with clinical symptoms of pain with the highest percentage oflow testosterone screening levels within the lower half of theappropriate reference range. The purpose of the study will be to showthe efficacy of open label androgen therapy in one of the groups alreadytested. The study will be similar in design to the screening study.Evaluations will take place at appropriate times during the study and atthe end of the study, be similar to Prophetic Example 1, and will alsoinclude baseline data. Patients will be provided with a verbal-anchoredVAS form and a patient questionnaire to assess their symptoms and levelof pain in a quantitative manner, similar at least in part to Example 1,to demonstrate efficacy of testosterone therapy in treating pain.Conventional statistical analysis will be applied.

Prophetic Example 3

Double Blind Placebo Controlled Study of Patients with Pain.

Based on the results of the previous study described above, a larger,and longer, clinical trial will be conducted in the most appropriatesubsets of patients. Patients will first be screened for testosteronelevels in the lower half of the appropriate reference range. They willthen be assigned randomly to one of the following regimens: 1) placebodaily for three months; 2) androgen therapy comprising testosterone orother bioactive androgen for three months. Treatment will be randomizedto an active treatment group with pain and a placebo treatment groupwithout pain. An open label extension study may be added as well. Whilethe treatments, the evaluations, and the analyses will be similar to theprevious studies, much more specific information will be generated fromthis study since the study will be larger and longer. Evaluations andtesting will be similar to Prophetic Examples 1 and 2.

Prophetic Example 4

Population Study in Patients with Low Thresholds of Pain.

Using Prophetic Examples 1-3 as a model, patient populations will beselected based on the above criteria but with a goal of studyingindividuals with low pain thresholds. Some of these patients will alsolack a feeling of well-being combined with a low threshold of pain.Patients with longstanding stressors in their lives as defined by afailure or poor ability to resolve states of stress, or the maintenanceof a maladaptive state of “distress,” will be tested for levels of freetestosterone. Once low androgen levels have been established as being inthe lower half of the appropriate reference range, a low threshold oftolerance to pain will be documented before treatment. Patients will bepain threshold-tested or challenged using any of a number of methods,including but not limited to the following: validated motor functionallimitations testing coupled with pain assessment (Mannerkorpi et al.,1999 Arthritis Care and Research, 12: 193), application of pressure tospecific susceptible tender points of the skin by a dolorimeter coupledwith VAS pain scoring (standard rheumatologic assessment technique), orthe application of controlled increases in pressure stimuli by hydraulicpiston to the left thumbnail coupled with VAS pain scoring (Gracely etal., 2002 Arthritis & Rheumatism 46: 1333). Additional methods ofevaluating pain and discomfort may include, in addition to the previouspain threshold testing, the SF-36 Health Survey, metrics for physicalfunction and psychological function, and/or other similar validatedinstruments and metrics. Thus, an open label population study will beconducted in patients with one of many longstanding stressors, whosetestosterone levels are shown to be in the lower half of the appropriatereference range, and whose pain threshold is low. Androgen therapy willthen be utilized to safely and effectively increase the patient'stestosterone level to show significant improvement in the low painthreshold.

Prophetic Example 5

Open Label Testosterone Therapy Study of Patients with Low Thresholds ofPain.

Subsequent to the population study, a Proof of Concept Study willfollow. It will be a study similar to the Population Study, and willfollow a protocol similar to Prophetic Example 2. One of the groupsevaluated above will be chosen as a test population for an efficacystudy preliminary to larger clinical trials.

Prophetic Example 6

Double Blind Placebo Controlled Study of Patients with Low Thresholds ofPain.

Subsequent to the Proof of Concept Study, a blinded placebo controlledstudy will follow. It will be a study similar to the Proof of ConceptStudy and will be a larger, and longer, clinical trial based on theresults of the previous study in one of the various subsets of patientswith an increase threshold of pain. This study will follow a protocolsimilar to Prophetic Example 3.

One of skill in the art would also know how to vary a test protocol asdescribed, in order to obtain the best, most accurate, and mostreproducible results.

While various embodiments of the present invention have been describedabove, it should be understood that such disclosures have been presentedby way of example only, and are not limiting. Thus, the breadth andscope of the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

Having now fully described the invention, it will be understood by thoseof ordinary skill in the art that the same can be performed within awide and equivalent range of conditions, formulations and otherparameters without affecting the scope of the invention or anyembodiment thereof. All patents, patent applications, and publicationscited herein are fully incorporated by reference in their entirety.

1-86. (canceled)
 87. A method of reducing chronic inflammatory pain in ahuman testosterone-deficient subject in need thereof, comprising:administering a composition comprising a pain-reducing amount oftestosterone to the subject, wherein the subject has testosterone levelsin the lower half of the appropriate reference range, and the methodreduces chronic inflammatory pain in the human testosterone-deficientsubject in need thereof.
 88. The method of claim 87, wherein thesubject's testosterone serum levels are restored from the baseline tothe middle to upper range of an appropriate reference range.
 89. Themethod of claim 87, wherein the subject further suffers from at leastone androgen-deficiency symptom selected from the group consisting of:elevated C-reactive protein; elevated erythrocyte sedimentation rate;and an unresolvable stressor state.
 90. The method of claim 89, whereinthe unresolvable stressor state is selected from the group consisting ofpost-traumatic stress disorder (PTSD), accident, trauma, surgery,autoimmune disease, chronic unresolved or acute viral infection,infectious disease, cancer, chronic exhaustion or physical distress,neuropathy, hyperalgesia, allodynia, grief, emotional distress,depression, dysthymia, surgical gonadectomy, pharmacologic-inducedgonadectomy, DSM-IV disorder 307.80, and DSM-IV disorder 307.89.
 91. Themethod of claim 87, wherein the composition is administered incombination with an antidepressant selected from the group consisting ofa tricyclic antidepressant, a serotonin-norepinephrine reuptakeinhibitor (SNRI), and a selective serotonin reuptake inhibitor (SSRI).92. The method of claim 87, wherein the composition is administered todeliver a daily unit dose of about 1.0 mg to about 12.8 mg of thetestosterone to a female human subject, wherein the administrationresults in steady state total testosterone serum levels without raisingfree testosterone serum levels or twenty-four hour free testosterone AUCabove the levels required for therapeutic efficacy and safety, whereinthe administration is selected from the group consisting of transdermaladministration, oral administration, parenteral administration,intramuscular administration, and buccal administration.
 93. The methodof claim 92, wherein the composition is formulated as a gel fortransdermal administration, wherein the gel comprises the testosteroneand a pharmaceutically acceptable carrier.
 94. The method of claim 92,wherein the daily unit dose of the testosterone is selected to maintainsteady state total testosterone serum levels within a range of betweenabout 0.9 ng/mL to about 1.4 ng/mL within 24 hours after administration.95. The method of claim 92, wherein the free testosterone serum levelsare raised to about 1.00 pg/mL to about 3.30 pg/mL and the twenty-fourhour free testosterone AUC levels are raised to about 40 pg-h/mL toabout 65 pg-h/mL.
 96. The method of claim 87, wherein the composition isadministered to deliver a daily unit dose of about 35 mg to about 100 mgof testosterone to a male human subject, wherein the administrationresults in steady state total testosterone serum levels without raisingfree testosterone serum levels or twenty-four hour free testosterone AUCabove the levels required for therapeutic efficacy and safety, whereinthe administration is selected from the group consisting of transdermaladministration, oral administration, parenteral administration,intramuscular administration, and buccal administration.
 97. The methodof claim 96, wherein the daily unit dose of the androgen is selected tomaintain steady state total androgen serum levels within a range ofbetween about 2.4 ng/mL to about 9.5 ng/mL within 24 hours afteradministration.
 98. The method of claim 96, wherein the free androgenserum levels are raised to about 90 pg/mL to about 300 pg/mL and thetwenty-four hour free androgen AUC levels are raised to about 350pg-h/mL to about 800 pg-h/mL.
 99. The method of claim 87, wherein thecomposition consists essentially of the testosterone and at least onepharmaceutically acceptable carrier.
 100. The method of claim 87,wherein the human subject has low endogenous opioid peptide levels andthe composition increases the endogenous opioid peptide production inthe human subject.
 101. The method of claim 100, wherein the opioidpeptides are selected from the group consisting of enkephalins,endorphins, dynorphins, adrenorphin, amidorphin, and opiorphin.
 102. Themethod of claim 100, wherein the endogenous opioid peptide levels aremeasured in cerebrospinal fluid.
 103. A method of increasing the painthreshold in a human testosterone-deficient subject in need thereof,comprising administering a composition comprising a pain-thresholdincreasing amount of a testosterone to the subject, wherein the subjecthas testosterone levels in the lower half of the appropriate referencerange, and the method increases the subject's pain-threshold.
 104. Themethod of claim 103, wherein the subject's testosterone serum levels arerestored from the baseline to the middle to upper range of anappropriate reference range.
 105. The method of claim 103, wherein thesubject further suffers from at least one androgen-deficiency symptomselected from the group consisting of: elevated C-reactive protein;elevated erythrocyte sedimentation rate; and an unresolvable stressorstate.
 106. The method of claim 105, wherein the unresolvable stressorstate is selected from the group consisting of post-traumatic stressdisorder (PTSD), accident, trauma, surgery, autoimmune disease, chronicunresolved or acute viral infection, infectious disease, cancer, chronicexhaustion or physical distress, neuropathy, hyperalgesia, allodynia,grief, emotional distress, depression, dysthymia, surgical gonadectomy,pharmacologic-induced gonadectomy, DSM-IV disorder 307.80, and DSM-IVdisorder 307.89.
 107. The method of claim 103, wherein the compositionis administered in combination with an antidepressant selected from thegroup consisting of a tricyclic antidepressant, aserotonin-norepinephrine reuptake inhibitor (SNRI), and a selectiveserotonin reuptake inhibitor (SSRI).
 108. The method of claim 103,wherein the composition is administered to deliver a daily unit dose ofabout 1.0 mg to about 12.8 mg of the testosterone to a female humansubject, wherein the administration results in steady state totaltestosterone serum levels without raising free testosterone serum levelsor twenty-four hour free testosterone AUC above the levels required fortherapeutic efficacy and safety, wherein the administration is selectedfrom the group consisting of transdermal administration, oraladministration, parenteral administration, intramuscular administration,and buccal administration.
 109. The method of claim 108, wherein thecomposition is formulated as a gel for transdermal administration,wherein the gel comprises the testosterone and a pharmaceuticallyacceptable carrier.
 110. The method of claim 108, wherein the daily unitdose of the testosterone is selected to maintain steady state totaltestosterone serum levels within a range of between about 0.9 ng/mL toabout 1.4 ng/mL within 24 hours after administration.
 111. The method ofclaim 108, wherein the free testosterone serum levels are raised toabout 1.00 pg/mL to about 3.30 pg/mL and the twenty-four hour freetestosterone AUC levels are raised to about 40 pg-h/mL to about 65pg-h/mL.
 112. The method of claim 103, wherein the composition isadministered to deliver a daily unit dose of about 35 mg to about 100 mgof testosterone to a male human subject, wherein the administrationresults in steady state total testosterone serum levels without raisingfree testosterone serum levels or twenty-four hour free testosterone AUCabove the levels required for therapeutic efficacy and safety, whereinthe administration is selected from the group consisting of transdermaladministration, oral administration, parenteral administration,intramuscular administration, and buccal administration.
 113. The methodof claim 112, wherein the daily unit dose of the androgen is selected tomaintain steady state total androgen serum levels within a range ofbetween about 2.4 ng/mL to about 9.5 ng/mL within 24 hours afteradministration.
 114. The method of claim 112, wherein the free androgenserum levels are raised to about 90 pg/mL to about 300 pg/mL and thetwenty-four hour free androgen AUC levels are raised to about 350pg-h/mL to about 800 pg-h/mL.
 115. The method of claim 103, wherein thecomposition consists essentially of the testosterone and at least onepharmaceutically acceptable carrier.